This document is an unofficial reference manual for LaTeX, a document preparation system, version of October 2015.

This manual was originally translated from LATEX.HLP v1.0a in the VMS Help Library.  The pre-translation version was written by George D. Greenwade of Sam Houston State University.  The LaTeX 2.09 version was written by Stephen Gilmore.  The LaTeX2e version was adapted from this by Torsten Martinsen.  Karl Berry made further updates and additions, and gratefully acknowledges using Hypertext Help with LaTeX, by Sheldon Green, and LaTeX Command Summary (for LaTeX 2.09) by L. Botway and C. Biemesderfer (published by the TeX Users Group as TeXniques number 10), as reference material (no text was directly copied).

Copyright 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Karl Berry.

Copyright 1988, 1994, 2007 Stephen Gilmore.

Copyright 1994, 1995, 1996 Torsten Martinsen.

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions.

LaTeX2e: An unofficial reference manual
***************************************

This document is an unofficial reference manual (version of October 2015) for LaTeX2e, a document preparation system.

About this document
*******************

This is an unofficial reference manual for the LaTeX2e document preparation system, which is a macro package for the TeX typesetting program (see Overview).  This document's home page is http://home.gna.org/latexrefman.  That page has links to the current output in various formats, sources, mailing list archives and subscriptions, and other infrastructure.

In this document, we will mostly just use `LaTeX' rather than `LaTeX2e', since the previous version of LaTeX (2.09) was retired many years ago.

LaTeX is currently maintained by a group of volunteers (http://latex-project.org).  The official documentation written by the LaTeX project is available from their web site.  This document is completely unofficial and has not been reviewed by the LaTeX maintainers.  Do not send bug reports or anything else about this document to them.  Instead, please send all comments to latexrefman-discuss@gna.org.

This document is a reference.  There is a vast array of other sources of information about LaTeX, at all levels.  Here are a few introductions.

http://ctan.org/pkg/latex-doc-ptr
     Two pages of recommended references to LaTeX documentation.

http://ctan.org/pkg/first-latex-doc
     Writing your first document, with a bit of both text and math.

http://ctan.org/pkg/usrguide
     The guide for document authors that is maintained as part of LaTeX; there are plenty of others available elsewhere.

http://ctan.org/pkg/lshort
     A short introduction to LaTeX, translated to many languages.

http://tug.org/begin.html
     Introduction to the TeX system, including LaTeX, with further references.

Overview of LaTeX
*****************

LaTeX is a system for typesetting documents.  It was originally created by Leslie Lamport and is now maintained by a group of volunteers (http://latex-project.org).  It is widely used, particularly for complex and technical documents, such as those involving mathematics.

A LaTeX user writes an input file containing text along with interspersed commands, for instance commands describing how the text should be formatted.  It is implemented as a set of related commands that interface with Donald E. Knuth's TeX typesetting program (the technical term is that LaTeX is a macro package for the TeX engine).  The user produces the output document by giving that input file to the TeX engine.

The term LaTeX is also sometimes used to mean the language in which the document is marked up, that is, to mean the set of commands available to a LaTeX user.

The name LaTeX is short for ``Lamport TeX''.  It is pronounced LAH-teck or LAY-teck, or sometimes LAY-tecks.  Inside a document, produce the logo with \LaTeX.  Where use of the logo is not sensible, such as in plain text, write it as LaTeX.

Starting and ending
===================

old name

LaTeX files have a simple global structure, with a standard beginning and ending.  Here is a ``hello, world'' example:

     \documentclass{article}
     \begin{document}
     Hello, \LaTeX\ world.
     \end{document}

Here, the article is the so-called document class, implemented in a file article.cls.  Any document class can be used.  A few document classes are defined by LaTeX itself, and vast array of others are widely available.  See Document classes.

You can include other LaTeX commands between the \documentclass and the \begin{document} commands. This area is called the preamble.

The \begin{document} ... \end{document} is a so-called environment; the document environment (and no others) is required in all LaTeX documents (see document).  LaTeX provides many environments itself, and many more are defined separately. See Environments.

The following sections discuss how to produce PDF or other output from a LaTeX input file.

Output files
============

LaTeX produces a main output file and at least two accessory files. The main output file's name ends in either .dvi or .pdf.

.dvi
     If LaTeX is invoked with the system command latex then it produces a DeVice Independent file, with extension .dvi.  You can view this file with a command such as xdvi, or convert it to a PostScript .ps file with dvips or to a Portable Document Format .pdf file with dvipdfmx. The contents of the file can be dumped in human-readable form with dvitype.  A vast array of other DVI utility programs are available (http://mirror.ctan.org/tex-archive/dviware).

.pdf
     If LaTeX is invoked via the system command pdflatex, among other commands (see TeX engines), then the main output is a Portable Document Format (PDF) file.  Typically this is a self-contained file, with all fonts and images included.

LaTeX also produces at least two additional files.

.log
     This transcript file contains summary information such as a list of loaded packages.  It also includes diagnostic messages and perhaps additional information for any errors.

.aux
     Auxiliary information is used by LaTeX for things such as cross references.  For example, the first time that LaTeX finds a forward reference---a cross reference to something that has not yet appeared in the source---it will appear in the output as a doubled question mark ??.  When the referred-to spot does eventually appear in the source then LaTeX writes its location information to this .aux file.  On the next invocation, LaTeX reads the location information from this file and uses it to resolve the reference, replacing the double question mark with the remembered location.

LaTeX may produce yet more files, characterized by the filename ending.  These include a .lof file that is used to make a list of figures, a .lot file used to make a list of tables, and a .toc file used to make a table of contents.  A particular class may create others; the list is open-ended.

TeX engines
===========

LaTeX is defined to be a set of commands that are run by a TeX implementation (see Overview).  This section gives a terse overview of the main programs.

latex
pdflatex
     In TeX Live (http://tug.org/texlive), if LaTeX is invoked via either the system command latex or pdflatex, then the pdfTeX engine is run (http://ctan.org/pkg/pdftex). When invoked as latex, the main output is a .dvi file; as pdflatex, the main output is a .pdf file.

     pdfTeX incorporates the e-TeX extensions to Knuth's original program (http://ctan.org/pkg/etex), including additional programming features and bi-directional typesetting, and has plenty of extensions of its own.  e-TeX is available on its own as the system command etex, but this is plain TeX (and produces .dvi).

     In other TeX distributions, latex may invoke e-TeX rather than pdfTeX.  In any case, the e-TeX extensions can be assumed to be available in LaTeX.

lualatex
     If LaTeX is invoked via the system command lualatex, the LuaTeX engine is run (http://ctan.org/pkg/luatex).  This program allows code written in the scripting language Lua (http://luatex.org) to interact with TeX's typesetting. LuaTeX handles UTF-8 Unicode input natively, can handle OpenType and TrueType fonts, and produces a .pdf file by default. There is also dvilualatex to produce a .dvi file, but this is rarely used.

xelatex
     If LaTeX is invoked with the system command xelatex, the XeTeX engine is run (http://tug.org/xetex).  Like LuaTeX, XeTeX natively supports UTF-8 Unicode and TrueType and OpenType fonts, though the implementation is completely different, mainly using external libraries instead of internal code.  XeTeX produces a .pdf file as output; it does not support DVI output.

     Internally, XeTeX creates an .xdv file, a variant of DVI, and translates that to PDF using the (x)dvipdfmx program, but this process is automatic.  The .xdv file is only useful for debugging.

Other variants of LaTeX and TeX exist, e.g., to provide additional support for Japanese and other languages ([u]pTeX, http://ctan.org/pkg/ptex, http://ctan.org/pkg/uptex).

LaTeX command syntax
====================

In the LaTeX input file, a command name starts with a backslash character, \.  The name itself then consists of either (a) a string of letters or (b) a single non-letter.

LaTeX commands names are case sensitive so that \pagebreak differs from \Pagebreak (the latter is not a standard command). Most commands are lowercase, but in any event you must enter all commands in the same case as they are defined.

A command may be followed by zero, one, or more arguments. These arguments may be either required or optional.  Required arguments are contained in curly braces, {...}.  Optional arguments are contained in square brackets, [...].  Generally, but not universally, if the command accepts an optional argument, it comes first, before any required arguments.

Inside of an optional argument, to use the character close square bracket (]) hide it inside curly braces, as in \item[closing bracket {]}].  Similarly, if an optional argument comes last, with no required argument after it, then to make the first character of the following text be an open square bracket, hide it inside curly braces.

LaTeX has the convention that some commands have a * form that is related to the form without a *, such as \chapter and \chapter*.  The exact difference in behavior varies from command to command.

This manual describes all accepted options and *-forms for the commands it covers (barring unintentional omissions, a.k.a. bugs).

Synopsis:

     \begin{ENVIRONMENT NAME}
       ..
     \end{ENVIRONMENT NAME}

An area of LaTeX source, inside of which there is a distinct behavior.  For instance, for poetry in LaTeX put the lines between \begin{verse} and \end{verse}.

     \begin{verse}
         There once was a man from Nantucket \\
          ..
     \end{verse}

The ENVIRONMENT NAME at the beginning must exactly match that at the end.  This includes the case where ENVIRONMENT NAME ends in a star (*); both the \begin and \end texts must include the star.

Environments may have arguments, including optional arguments.  This example produces a table.  The first argument is optional (and causes the table to be aligned on its top row) while the second argument is required (it specifies the formatting of columns).

     \begin{tabular}[t]{r|l}
       .. rows of table ..
     \end{tabular}

A command that changes the value, or changes the meaning, of some other command or parameter.  For instance, the \mainmatter command changes the setting of page numbers from roman numerals to arabic.

Document classes
****************

The document's overall class is defined with this command, which is normally the first command in a LaTeX source file.

     \documentclass[OPTIONS]{CLASS}

The following document CLASS names are built into LaTeX. (Many other document classes are available as separate packages; see Overview.)

article
     For a journal article, a presentation, and miscellaneous general use.

book
     Full-length books, including chapters and possibly including front matter, such as a preface, and back matter, such as an appendix (see Front/back matter).

letter
     Mail, optionally including mailing labels (see Letters).

report
     For documents of length between an article and a book, such as technical reports or theses, which may contain several chapters.

slides
     For slide presentations---rarely used today.  In its place the beamer package is perhaps the most prevalent (see beamer template).

Standard OPTIONS are described in the next section.

Document class options
======================

You can specify so-called global options or class options to the \documentclass command by enclosing them in square brackets. To specify more than one OPTION, separate them with a comma, as in:

     \documentclass[OPTION1,OPTION2,...]{CLASS}

Here is the list of the standard class options.

All of the standard classes except slides accept the following options for selecting the typeface size (default is 10pt):

     10pt  11pt  12pt

All of the standard classes accept these options for selecting the paper size (these show height by width):

a4paper
     210 by 297 mm (about 8.25 by 11.75 inches)

b5paper
     176 by 250 mm (about 7 by 9.875 inches)

executivepaper
     7.25 by 10.5 inches

legalpaper
     8.5 by 14 inches

letterpaper
     8.5 by 11 inches (the default)

When using one of the engines pdfLaTeX, LuaLaTeX, or XeLaTeX (see TeX engines), options other than letterpaper set the print area but you must also set the physical paper size.  One way to do that is to put \pdfpagewidth=\paperwidth and \pdfpageheight=\paperheight in your document's preamble.  The geometry package provides flexible ways of setting the print area and physical page size.

Miscellaneous other options:

draft
final
     Mark (draft) or do not mark (final) overfull boxes with a black box in the margin; default is final.

fleqn
     Put displayed formulas flush left; default is centered.

landscape
     Selects landscape format; default is portrait.

leqno
     Put equation numbers on the left side of equations; default is the right side.

openbib
     Use ``open'' bibliography format.

titlepage
notitlepage
     Specifies whether the title page is separate; default depends on the class.

The following options are not available with the slides class.

onecolumn
twocolumn
     Typeset in one or two columns; default is onecolumn.

oneside
twoside
     Selects one- or two-sided layout; default is oneside, except that in the book class the default is twoside.

     For one-sided printing, the text is centered on the page.  For two-sided printing, the \evensidemargin (\oddsidemargin) parameter determines the distance on even (odd) numbered pages between the left side of the page and the text's left margin, with \oddsidemargin being 40% of the difference between \paperwidth and \textwidth, and \evensidemargin is the remainder.

openright
openany
     Determines if a chapter should start on a right-hand page; default is openright for book, and openany for report.

The slides class offers the option clock for printing the time at the bottom of each note.

Additional packages are loaded like this:

     \usepackage[OPTIONS]{PKG}

To specify more than one package, you can separate them with a comma, as in \usepackage{PKG1,PKG2,...}, or use multiple \usepackage commands.

Any options given in the \documentclass command that are unknown by the selected document class are passed on to the packages loaded with \usepackage.

Fonts
*****

old name

Two important aspects of selecting a font are specifying a size and a style.  The LaTeX commands for doing this are described here.

Font styles
===========

The following type style commands are supported by LaTeX.

This first group of commands is typically used with an argument, as in \textit{TEXT}.  In the table below, the corresponding command in parenthesis is the ``declaration form'', which takes no arguments, as in {\itshape TEXT}.  The scope of the declaration form lasts until the next type style command or the end of the current group.

These commands, in both the argument form and the declaration form, are cumulative; e.g., you can say either \sffamily\bfseries or \bfseries\sffamily to get bold sans serif.

You can alternatively use an environment form of the declarations; for instance, \begin{ttfamily}...\end{ttfamily}.

These font-switching commands automatically insert italic corrections if needed.  (see \/, for the details of italic corrections.) Specifically, they insert the italic correction unless the following character is in the list \nocorrlist, which by default consists of a period and a comma.  To suppress the automatic insertion of italic correction, use \nocorr at the start or end of the command argument, such as \textit{\nocorr text} or \textsc{text \nocorr}.

\textrm (\rmfamily)
     Roman.

\textit (\itshape)
     Italics.

\textmd (\mdseries)
     Medium weight (default).

\textbf (\bfseries)
     Boldface.

\textup (\upshape)
     Upright (default).

\textsl (\slshape)
     Slanted.

\textsf (\sffamily)
     Sans serif.

\textsc (\scshape)
     Small caps.

\texttt (\ttfamily)
     Typewriter.

\textnormal (\normalfont)
     Main document font.

Although it also changes fonts, the \emph{TEXT} command is semantic, for text to be emphasized, and should not be used as a substitute for \textit.  For example, \emph{START TEXT \emph{MIDDLE TEXT} END TEXT} will result in the START TEXT and END TEXT in italics, but MIDDLE TEXT will be in roman.

LaTeX also provides the following commands, which unconditionally switch to the given style, that is, are not cumulative.  Also, they are used differently than the above commands: {\CMD...} instead of \CMD{...}.  These are two unrelated constructs.

\bf
     Switch to bold face.

\cal
     Switch to calligraphic letters for math.

\it
     Italics.

\rm
     Roman.

\sc
     Small caps.

\sf
     Sans serif.

\sl
     Slanted (oblique).

\tt
     Typewriter (monospace, fixed-width).

The \em command is the unconditional version of \emph.

(Some people consider the unconditional font-switching commands, such as \tt, obsolete and that only the cumulative commands (\texttt) should be used.  Others think that both sets of commands have their place and sometimes an unconditional font switch is precisely what you want; for one example, see description.)

The following commands are for use in math mode.  They are not cumulative, so \mathbf{\mathit{SYMBOL}} does not create a boldface and italic SYMBOL; instead, it will just be in italics.  This is because typically math symbols need consistent typographic treatment, regardless of the surrounding environment.

\mathrm
     Roman, for use in math mode.

\mathbf
     Boldface, for use in math mode.

\mathsf
     Sans serif, for use in math mode.

\mathtt
     Typewriter, for use in math mode.

\mathit
(\mit)
     Italics, for use in math mode.

\mathnormal
     For use in math mode, e.g., inside another type style declaration.

\mathcal
     Calligraphic letters, for use in math mode.

In addition, the command \mathversion{bold} can be used for switching to bold letters and symbols in formulas. \mathversion{normal} restores the default.

Finally, the command \oldstylenums{NUMERALS} will typeset so-called ``old-style'' numerals, which have differing heights and depths (and sometimes widths) from the standard ``lining'' numerals, which all have the same height as upper-case letters.  LaTeX's default fonts support this, and will respect \textbf (but not other styles; there are no italic old-style numerals in Computer Modern).  Many other fonts have old-style numerals also; sometimes the textcomp package must be loaded, and sometimes package options are provided to make them the default.  FAQ entry: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=osf.

Font sizes
==========

The following standard type size commands are supported by LaTeX. The table shows the command name and the corresponding actual font size used (in points) with the 10pt, 11pt, and 12pt document size options, respectively (see Document class options).

Command    10pt    11pt    12pt
\tiny
5            6            6
\scriptsize
7            8            8
\footnotesize
8            9            10
\small
9            10           10.95
\normalsize (default)
10           10.95        12
\large
12           12           14.4
\Large
14.4         14.4         17.28
\LARGE
17.28        17.28        20.74
\huge
20.74        20.74        24.88
\Huge
24.88        24.88        24.88

The commands as listed here are ``declaration forms''. The scope of the declaration form lasts until the next type style command or the end of the current group.  You can also use the environment form of these commands; for instance, \begin{tiny}...\end{tiny}.

Low-level font commands
=======================

These commands are primarily intended for writers of macros and packages.  The commands listed here are only a subset of the available ones.

\fontencoding{ENCODING}
     Select the font encoding, the encoding of the output font. There are a large number of valid encodings.  The most common are OT1, Knuth's original encoding for Computer Modern (the default), and T1, also known as the Cork encoding, which has support for the accented characters used by the most widespread European languages (German, French, Italian, Polish and others), which allows TeX to hyphenate words containing accented letters.

\fontfamily{FAMILY}
     Select the font family.  The web page http://www.tug.dk/FontCatalogue/ provides one way to browse through many of the fonts easily used with LaTeX.  Here are examples of some common families:

       pag  Avant Garde

       fvs  Bitstream Vera Sans

       pbk  Bookman

       bch  Charter

       ccr  Computer Concrete

       cmr  Computer Modern

       pcr  Courier

       phv  Helvetica

       fi4  Inconsolata

       lmr  Latin Modern

       lmss Latin Modern Sans

       lmtt Latin Modern Typewriter

       pnc  New Century Schoolbook

       ppl  Palatino

       ptm  Times

       uncl Uncial

       put  Utopia

       pzc  Zapf Chancery

\fontseries{SERIES}
     Select the font series.  A series combines a weight and a width.  Typically, a font supports only a few of the possible combinations.  Some common combined series values include:

       m  Medium (normal)

       b  Bold

       c  Condensed

       bc Bold condensed

       bx Bold extended

     The possible values for weight, individually, are:

       ul Ultra light

       el Extra light

       l  Light

       sl Semi light

       m  Medium (normal)

       sb Semi bold

       b  Bold

       eb Extra bold

       ub Ultra bold

     The possible values for width, individually, are (the percentages are just guides and are not followed precisely by all fonts):

       uc Ultra condensed, 50%

       ec Extra condensed, 62.5%

       c  Condensed, 75%

       sc Semi condensed, 87.5%

       m  Medium, 100%

       sx Semi expanded, 112.5%

       x  Expanded, 125%

       ex Extra expanded, 150%

       ux Ultra expanded, 200%

     When forming the SERIES string from the weight and width, drop the m that stands for medium weight or medium width, unless both weight and width are m, in which case use just one (m).

\fontshape{SHAPE}
     Select font shape. Valid shapes are:

       n  Upright (normal)

       it Italic

       sl Slanted (oblique)

       sc Small caps

       ui Upright italics

       ol Outline

     The two last shapes are not available for most font families, and small caps are often missing as well.

\fontsize{SIZE}{SKIP}
     Set the font size and the line spacing.  The unit of both parameters defaults to points (pt).  The line spacing is the nominal vertical space between lines, baseline to baseline.  It is stored in the parameter \baselineskip.  The default \baselineskip for the Computer Modern typeface is 1.2 times the \fontsize. Changing \baselineskip directly is inadvisable since its value is reset every time a size change happens; see \baselinestretch, next.

\baselinestretch
     LaTeX multiplies the line spacing by the value of the \baselinestretch parameter; the default factor is 1.  A change takes effect when \selectfont (see below) is called.  You can make line skip changes happen for the entire document by doing \renewcommand{\baselinestretch}{2.0} in the preamble.

     However, the best way to double-space a document is to use the setspace package.  In addition to offering a number of spacing options, this package keeps the line spacing single-spaced in places where that is typically desirable, such as footnotes and figure captions.  See the package documentation.

\linespread{FACTOR}
     Equivalent to \renewcommand{\baselinestretch}{FACTOR}, and therefore must be followed by \selectfont to have any effect. Best specified in the preamble, or use the setspace package, as just described.

\selectfont
     The effects of the font commands described above do not happen until \selectfont is called, as in \fontfamily{FAMILYNAME}\selectfont.  It is often useful to put this in a macro:

     \newcommand*{\myfont}{\fontfamily{FAMILYNAME}\selectfont}

     (see \newcommand & \renewcommand).

\usefont{ENC}{FAMILY}{SERIES}{SHAPE}
     The same as invoking \fontencoding, \fontfamily, \fontseries and \fontshape with the given parameters, followed by \selectfont.  For example:

          \usefont{ot1}{cmr}{m}{n}

Layout
******

Commands for controlling the general page layout.

\onecolumn
==========

The \onecolumn declaration starts a new page and produces single-column output.  If the document is given the class option onecolumn then this is the default behavior (see Document class options).

This command is fragile (see \protect).

\twocolumn
==========

Synopsis:

     \twocolumn[PRELIM ONE COLUMN TEXT]

The \twocolumn declaration starts a new page and produces two-column output. If the document is given the class option twocolumn then this is the default (see Document class options).

If the optional PRELIM ONE COLUMN TEXT argument is present, it is typeset in one-column mode before the two-column typesetting starts.

This command is fragile (see \protect).

These parameters control typesetting in two-column output:

\columnsep
     The distance between columns. The default is 35pt.  Change it with a command such as \setlength{\columnsep}{40pt} You must change it before the two column environment starts; in the preamble is a good place.

\columnseprule
     The width of the rule between columns. The rule appears halfway between the two columns.  The default is 0pt, meaning that there is no rule. Change it with a command such as \setlength{\columnseprule}{0.4pt}, before the two-column environment starts.

\columnwidth
     The width of a single column.  In one-column mode this is equal to \textwidth.  In two-column mode by default LaTeX sets the width of each of the two columns to be half of \textwidth minus \columnsep.

In a two-column document, the starred environments table* and figure* are two columns wide, whereas the unstarred environments table and figure take up only one column (see figure and see table). LaTeX places starred floats at the top of a page. The following parameters control float behavior of two-column output.

\dbltopfraction
     The maximum fraction at the top of a two-column page that may be occupied by two-column wide floats.  The default is 0.7, meaning that the height of a table* or figure* environment must not exceed 0.7\textheight .  If the height of your starred float environment exceeeds this then you can take one of the following actions to prevent it from floating all the way to the back of the document:

       * Use the [tp] location specifier to tell LaTeX to try to put the bulky float on a page by itself, as well as at the top of a page.

       * Use the [t!] location specifier to override the effect of \dbltopfraction for this particular float.

       * Increase the value of \dbltopfraction to a suitably large number, to avoid going to float pages so soon.

     You can redefine it, for instance with \renewcommand{\dbltopfraction}{0.9}.

\dblfloatpagefraction
     For a float page of two-column wide floats, this is the minimum fraction that must be occupied by floats, limiting the amount of blank space. LaTeX's default is 0.5.  Change it with \renewcommand.

\dblfloatsep
     On a float page of two-column wide floats, this length is the distance between floats, at both the top and bottom of the page.  The default is 12pt plus2pt minus2pt for a document set at 10pt or 11pt, and 14pt plus2pt minus4pt for a document set at 12pt.

\dbltextfloatsep
     This length is the distance between a multi-column float at the top or bottom of a page and the main text.  The default is 20pt plus2pt minus4pt.

\dbltopnumber
     On a float page of two-column wide floats, this counter gives the maximum number of floats allowed at the top of the page.  The LaTeX default is 2.

This example shows the use of the optional argument of \twocolumn to create a title that spans the two-column article:

     \documentclass[twocolumn]{article}
     \newcommand{\authormark}[1]{\textsuperscript{#1}}
     \begin{document}
     \twocolumn[{% inside this optional argument goes one-column text
      \centering
      \LARGE The Title \\[1.5em]
      \large Author One\authormark{1},
             Author Two\authormark{2},
             Author Three\authormark{1} \\[1em]
      \normalsize
      \begin{tabular}{p{.2\textwidth}@{\hspace{2em}}p{.2\textwidth}}
        \authormark{1}Department one  &\authormark{2}Department two \\
         School one                   &School two
      \end{tabular}\\[3em] % space below title part
     }]

     Two column text here.

\flushbottom
============

The \flushbottom command can go at any point in the document body.  It makes all later pages the same height, stretching the vertical space where necessary to fill out the page.

If TeX cannot satisfactorily stretch the vertical space in a page then you get a message like Underfull \vbox (badness 10000) has occurred while \output is active.  You can change to \raggedbottom (see below).  Alternatively, you can try to adjust the textheight to be compatible, or you can add some vertical stretch glue between lines or between paragraphs, as in \setlength{\parskip}{0ex plus0.1ex}.  In a final editing stage you can adjust the height of individual pages (see \enlargethispage).

This is the default only if you select the twoside document class option (see Document class options).

\raggedbottom
=============

The \raggedbottom command can go at any point in the document body.  It makes all later pages the natural height of the material on that page; no rubber lengths will be stretched.  Thus, in a two-sided document the facing pages may be different heights.  See also \flushbottom above.

This is the default unless you select the twoside document class option (see Document class options).

Page layout parameters
======================

\columnsep
\columnseprule
\columnwidth
     The distance between the two columns, the width of a rule between the columns, and the width of the columns, when the document class option twocolumn is in effect (see Document class options). See \twocolumn.

\headheight
     Height of the box that contains the running head.  The default in the article, report, and book classes is 12pt, at all type sizes.

\headsep
     Vertical distance between the bottom of the header line and the top of the main text.  The default in the article and report classes is 25pt.  In the book class the default is: if the document is set at 10pt then it is 0.25in, and at 11pt and 12pt it is 0.275in.

\footskip
     Distance from the baseline of the last line of text to the baseline of the page footer.  The default in the article and report classes is 30pt.  In the book class the default is: when the type size is 10pt the default is 0.35in, while at 11pt it is 0.38in, and at 12pt it is 30pt.

\linewidth
     Width of the current line, decreased for each nested list (see list).  That is, the nominal value for \linewidth is to equal \textwidth but for each nested list the \linewidth is decreased by the sum of that list's \leftmargin and \rightmargin (see itemize).

\marginparpush
\marginsep
\marginparwidth
     The minimum vertical space between two marginal notes, the horizontal space between the text body and the marginal notes, and the horizontal width of the notes.

     Normally marginal notes appear on the outside of the page, but the declaration \reversemarginpar changes that (and \normalmarginpar changes it back).

     The defaults for \marginparpush in both book and article classes are: 7pt if the document is set at 12pt, and 5pt if the document is set at 11pt or 10pt.

     For \marginsep, in article class the default is 10pt except if the document is set at 10pt and in two-column mode where the default is 11pt.

     For \marginsep in book class the default is 10pt in two-column mode and 7pt in one-column mode.

     For \marginparwidth in both book and article classes, in two-column mode the default is 60% of \paperwidth - \textwidth, while in one-column mode it is 50% of that distance.

\oddsidemargin
\evensidemargin
     The \oddsidemargin is the extra distance between the left side of the page and the text's left margin, on odd-numbered pages when the document class option twoside is chosen and on all pages when oneside is in effect.  When twoside is in effect, on even-numbered pages the extra distance on the left is evensidemargin.

     LaTeX's default is that \oddsidemargin is 40% of the difference between \paperwidth and \textwidth, and \evensidemargin is the remainder.

\paperheight
     The height of the paper, as distinct from the height of the print area. It is normally set with a document class option, as in \documentclass[a4paper]{article} (see Document class options).

\paperwidth
     The width of the paper, as distinct from the width of the print area. It is normally set with a document class option, as in \documentclass[a4paper]{article} (see Document class options).

\textheight
     The normal vertical height of the page body.  If the document is set at a nominal type size of 10pt then for an article or report the default is 43\baselineskip, while for a book it is 41\baselineskip.  At a type size of 11pt the default is 38\baselineskip for all document classes.  At 12pt it is 36\baselineskip for all classes.

\textwidth
     The full horizontal width of the entire page body.  For an article or report document, the default is 345pt when the chosen type size is 10pt, the default is 360pt at 11pt, and it is 390pt at 12pt.  For a book document, the default is 4.5in at a type size of 10pt, and 5in at 11pt or 12pt.

     In multi-column output, \textwidth remains the width of the entire page body, while \columnwidth is the width of one column (see \twocolumn).

     In lists (see list), \textwidth remains the width of the entire page body (and \columnwidth the width of the entire column), while \linewidth may decrease for nested lists.

     Inside a minipage (see minipage) or \parbox (see \parbox), all the width-related parameters are set to the specified width, and revert to their normal values at the end of the minipage or \parbox.

     This entry is included for completeness: \hsize is the TeX primitive parameter used when text is broken into lines.  It should not be used in normal LaTeX documents.

\topmargin
     Space between the top of the TeX page (one inch from the top of the paper, by default) and the top of the header.  The value is computed based on many other parameters: \paperheight - 2in - \headheight - \headsep - \textheight - \footskip, and then divided by two.

\topskip
     Minimum distance between the top of the page body and the baseline of the first line of text.  For the standard classes, the default is the same as the font size, e.g., 10pt at a type size of 10pt.

Floats
======

Some typographic elements, such as figures and tables, cannot be broken across pages.  They must be typeset outside of the normal flow of text, for instance floating to the top of a later page.

LaTeX can have a number of different classes of floating material. The default is the two classes, figure (see figure) and table (see table), but you can create a new class with the package float.

Within any one float class LaTeX always respects the order, so that the first figure in a document source must be typeset before the second figure.  However, LaTeX may mix the classes, so it can happen that while the first table appears in the source before the first figure, it appears in the output after it.

The placement of floats is subject to parameters, given below, that limit the number of floats that can appear at the top of a page, and the bottom, etc. If so many floats are queued up that the limits prevent them all from fitting on a page then LaTeX places what it can and defers the rest to the next page.  In this way, floats may be typset far from their place in the source.  In particular, a float that is big can migrate to the end of the document. But then because all floats in a class must appear in sequential order, every subsequent float in that class also appears at the end.

In addition to changing the parameters, for each float you can tweak where the float placement algorithm tries to place it by using its PLACEMENT argument.  The possible values are a sequence of the letters below. The default for both figure and table, in both article and book classes, is tbp.

t
     (Top)---at the top of a text page.

b
     (Bottom)---at the bottom of a text page.  (However, b is not allowed for full-width floats (figure*) with double-column output.  To ameliorate this, use the stfloats or dblfloatfix package, but see the discussion at caveats in the FAQ: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=2colfloat.

h
     (Here)---at the position in the text where the figure environment appears.  However, h is not allowed by itself; t is automatically added.

     To absolutely force a float to appear ``here'', you can \usepackage{float} and use the H specifier which it defines.  For further discussion, see the FAQ entry at http://www.tex.ac.uk/cgi-bin/texfaq2html?label=figurehere.

p
     (Page of floats)---on a separate float page, which is a page containing no text, only floats.

!
     Used in addition to one of the above; for this float only, LaTeX ignores the restrictions on both the number of floats that can appear and the relative amounts of float and non-float text on the page. The ! specifier does not mean ``put the float here''; see above.

Note: the order in which letters appear in the PLACEMENT argument does not change the order in which LaTeX tries to place the float; for instance, btp has the same effect as tbp.  All that PLACEMENT does is that if a letter is not present then the algorithm does not try that location.  Thus, LaTeX's default of tbp is to try every location except placing the float where it occurs in the source.

To prevent LaTeX from moving floats to the end of the document or a chapter you can use a \clearpage command to start a new page and insert all pending floats. If a pagebreak is undesirable then you can use the afterpage package and issue \afterpage{\clearpage}.  This will wait until the current page is finished and then flush all outstanding floats.

LaTeX can typeset a float before where it appears in the source (although on the same output page) if there is a t specifier in the PLACEMENT paramater.  If this is not desired, and deleting the t is not acceptable as it keeps the float from being placed at the top of the next page, then you can prevent it by either using the flafter package or using the command \suppressfloats[t], which causes floats for the top position on this page to moved to the next page.

Parameters relating to fractions of pages occupied by float and non-float text (change them with \renewcommand{PARAMETER}{DECIMAL BETWEEN 0 AND 1}):

\bottomfraction
     The maximum fraction of the page allowed to be occupied by floats at the bottom; default .3.

\floatpagefraction
     The minimum fraction of a float page that must be occupied by floats; default .5.

\textfraction
     Minimum fraction of a page that must be text; if floats take up too much space to preserve this much text, floats will be moved to a different page.  The default is .2.

\topfraction
     Maximum fraction at the top of a page that may be occupied before floats; default .7.

Parameters relating to vertical space around floats (change them with \setlength{PARAMETER}{LENGTH EXPRESSION}):

\floatsep
     Space between floats at the top or bottom of a page; default 12pt plus2pt minus2pt.

\intextsep
     Space above and below a float in the middle of the main text; default 12pt plus2pt minus2pt for 10 point and 11 point documents, and 14pt plus4pt minus4pt for 12 point documents.

\textfloatsep
     Space between the last (first) float at the top (bottom) of a page; default 20pt plus2pt minus4pt.

Counters relating to the number of floats on a page (change them with \setcounter{CTRNAME}{NATURAL NUMBER}):

bottomnumber
     Maximum number of floats that can appear at the bottom of a text page; default 1.

dbltopnumber
     Maximum number of full-sized floats that can appear at the top of a two-column page; default 2.

topnumber
     Maximum number of floats that can appear at the top of a text page; default 2.

totalnumber
     Maximum number of floats that can appear on a text page; default 3.

The principal TeX FAQ entry relating to floats http://www.tex.ac.uk/cgi-bin/texfaq2html?label=floats contains suggestions for relaxing LaTeX's default parameters to reduce the problem of floats being pushed to the end.  A full explaination of the float placement algorithm is Frank Mittelbach's article ``How to infuence the position of float environments like figure and table in LaTeX?''  http://latex-project.org/papers/tb111mitt-float.pdf.

Sectioning
**********

Sectioning commands provide the means to structure your text into units:

\part

\chapter
     (report and book class only)

\section

\subsection

\subsubsection

\paragraph

\subparagraph

All sectioning commands take the same general form, e.g.,

     \chapter[TOCTITLE]{TITLE}

In addition to providing the heading TITLE in the main text, the section title can appear in two other places:

 1. The table of contents.

 2. The running head at the top of the page.

You may not want the same text in these places as in the main text. To handle this, the sectioning commands have an optional argument TOCTITLE that, when given, specifies the text for these other places.

Also, all sectioning commands have *-forms that print TITLE as usual, but do not include a number and do not make an entry in the table of contents.  For instance:

     \section*{Preamble}

The \appendix command changes the way following sectional units are numbered.  The \appendix command itself generates no text and does not affect the numbering of parts.  The normal use of this command is something like

     \chapter{A Chapter}
     ...
     \appendix
     \chapter{The First Appendix}

The secnumdepth counter controls printing of section numbers. The setting

     \setcounter{secnumdepth}{LEVEL}

suppresses heading numbers at any depth > LEVEL, where chapter is level zero.  (see \setcounter.)

Cross references
****************

One reason for numbering things like figures and equations is to refer the reader to them, as in ``See Figure 3 for more details.''

\label
======

Synopsis:

     \label{KEY}

A \label command appearing in ordinary text assigns to KEY the number of the current sectional unit; one appearing inside a numbered environment assigns that number to KEY.  The assigned number can be retrieved with the \ref{KEY} command (see \ref).

Thus, in the example below the key sec:test holds the number of the current section and the key fig:test that of the figure. (Incidentally, labels must appear after captions in figures and tables.)

     \section{section name}
     \label{sec:test}
     This is Section~\ref{sec:test}.
     \begin{figure}
       ...
       \caption{caption text}
       \label{fig:test}
     \end{figure}
     See Figure~\ref{fig:test}.

A key name can consist of any sequence of letters, digits, or common punctuation characters.  Upper and lowercase letters are distinguished, as usual.

Although the name can be more or less anything, a common convention is to use labels consisting of a prefix and a suffix separated by a colon or period.  This helps to avoid accidentally creating two labels with the same name.  Some commonly-used prefixes:

ch
     for chapters

sec
     for lower-level sectioning commands

fig
     for figures

tab
     for tables

eq
     for equations

Thus, a label for a figure would look like fig:test or fig.test.

\pageref{KEY}
=============

Synopsis:

     \pageref{KEY}

The \pageref{KEY} command produces the page number of the place in the text where the corresponding \label{KEY} command appears.

\ref{KEY}
=========

Synopsis:

     \ref{KEY}

The \ref command produces the number of the sectional unit, equation, footnote, figure, ..., of the corresponding \label command (see \label).  It does not produce any text, such as the word `Section' or `Figure', just the bare number itself.

Environments
************

LaTeX provides many environments for marking off certain text. Each environment begins and ends in the same manner:

     \begin{ENVNAME}
     ...
     \end{ENVNAME}

abstract
========

Synopsis:

     \begin{abstract}
     ...
     \end{abstract}

Environment for producing an abstract, possibly of multiple paragraphs.

array
=====

Synopsis:

     \begin{array}{COLS}
     COLUMN 1 ENTRY &COLUMN 2 ENTRY ... &COLUMN N ENTRY \\
     ...
     \end{array}

or

     \begin{array}[POS]{COLS}
     COLUMN 1 ENTRY &COLUMN 2 ENTRY ... &COLUMN N ENTRY \\
     ...
     \end{array}

Produce a mathematical array.  This environment can only be used in math mode, and normally appears within a displayed mathematics environment such as equation (see equation).  Column entries are separated by an ampersand (&).  Rows are terminated with double-backslashes (\\) (see \\).

The required argument COLS describes the number of columns, their alignment, and the formatting of the intercolumn regions.  See tabular for the complete description of COLS, and of the other common features of the two environments, including the optional POS argument.

There are two ways that array diverges from tabular.  The first is that array entries are typeset in mathematics mode, in textstyle (except if the COLS definition specifies the column with @p{..}, which causes the entry to be typeset in text mode). The second is that, instead of tabular's parameter \tabcolsep, LaTeX's intercolumn space in an array is governed by \arraycolsep which gives half the width between columns. The default for this is 5pt.

To obtain arrays with braces the standard is to use the amsmath package.  It comes with environments pmatrix for an array surrounded by parentheses (..), bmatrix for an array surrounded by square brackets [..], Bmatrix for an array surrounded by curly braces {..}, vmatrix for an array surrounded by vertical bars |..|, and Vmatrix for an array surrounded by double vertical bars ||..||, along with a number of other array constructs.

Here is an example of an array:

     \begin{equation}
       \begin{array}{cr}
         \sqrt{y}  &12.3 \\
         x^2       &3.4
       \end{array}
     \end{equation}

center
======

Synopsis:

     \begin{center}
      .. text ..
     \end{center}

Environment to create a sequence of lines that are centered within the left and right margins on the current page.  If the text in the environment body is too long to fit on a line, LaTeX will insert line breaks that avoid hyphenation and avoid stretching or shrinking any interword space.  To force a line break at a particular spot use double-backslash \\ (see \\).

This environment inserts space above and below the text body.  See \centering to avoid such space, for example inside a figure environment.

In this example, depending on the line width, LaTeX may choose a break for the part before the double backslash, will center the line or two, then will break at the double backslash, and will center the ending.

     \begin{center}
       My father considered that anyone who went to chapel and didn't drink
       alcohol was not to be tolerated.\\
       I grew up in that belief.  --Richard Burton
     \end{center}

A double backslash after the final line is optional.

\centering
----------

Declaration that causes material in its scope to be centered.  It is most often used inside an environment such as figure, or in a parbox.

Unlike the center environment, the \centering command does not add vertical space above and below the text.

It also does not start a new paragraph; it simply changes how LaTeX formats paragraph units.  If ww {\centering xx \\ yy} zz is surrounded by blank lines then LaTeX will create a paragraph whose first line ww xx is centered and whose second line, not centered, contains yy zz.  Usually what is desired is for the scope of the declaration to contain a blank line or the \end command of an environment such as figure or table that ends the paragraph unit.  Thus, if {\centering xx \\ yy\par} zz is surrounded by blank lines then it makes a new paragraph with two centered lines xx and yy, followed by a new paragraph with zz that is formatted as usual.  See also the following example.

This example's \centering causes the graphic to be horizontally centered.

     \begin{figure}
       \centering
       \includegraphics[width=0.6\textwidth]{ctan_lion.png}
       \caption{CTAN Lion}  \label{fig:CTANLion}
     \end{figure}

The scope of the \centering ends with the \end{figure}.

description
===========

Synopsis:

     \begin{description}
     \item [FIRST LABEL] text of first item
     \item [SECOND LABEL] text of second item
       ...
     \end{description}

Environment to make a labelled list of items.  Each item's LABEL is typeset in bold, flush-left.  Each item's text may contain multiple paragraphs.  Although the labels on the items are optional there is no sensible default, so all items should have labels.

The list consists of at least one item; see \item (having no items causes the LaTeX error Something's wrong--perhaps a missing \item).  Each item is produced with an \item command.

Since the labels are in bold style, if the label text calls for a font change given in argument style (see Font styles) then it will come out bold.  For instance, if the label text calls for typewriter with \item[\texttt{label text}] then it will appear in bold typewriter, if that is available. The simplest way to get non-bolded typewriter is to use declaritive style \item[{\tt label text}]. Similarly, get normal text use \item[{\rm label text}].

For other major LaTeX labelled list environments, see itemize and enumerate.  For information about customizing list layout, see list; also, the package enumitem is useful for this.

This example shows the environment used for a sequence of definitions.

     \begin{definition}
       \item[lama] A priest.
       \item[llama] A beast.
     \end{definition}

displaymath
===========

Synopsis:

     \begin{displaymath}
       .. math text ..
     \end{displaymath}

Environment to typeset the math text on its own line, in display style and centered.  To make the text be flush-left use the global option fleqn; see Document class options.

LaTeX will not break the math text across lines.

In the displaymath environment no equation number is added to the math text. One way to get an equation number is to use the equation environment (see equation).

Note that the amsmath package has extensive displayed equation facilities.  Those facilities are the best approach for such output in new documents.  For example, there are a number of options in that package for having math text broken across lines.

The construct \[..math text..\] is essentially a synonym for \begin{displaymath}..math text..\end{displaymath} but the latter is easier to work with in the source file; for instance, searching for a square bracket may get false positives but the word displaymath will likely be unique.  (The construct $$..math text..$$ from Plain TeX is sometimes mistakenly used as a synonym for displaymath.  It is not a synonym, because the displaymath environment checks that it isn't started in math mode and that it ends in math mode begun by the matching environment start, because the displaymath environment has different vertical spacing, and because the displaymath environment honors the fleqn option.)

The output from this example is centered and alone on its line.

     \begin{displaymath}
       \int_1^2 x^2\,dx=7/3
     \end{displaymath}

Also, the integral sign is larger than the inline version \( \int_1^2 x^2\,dx=7/3 \) produces.

document
========

The document environment encloses the entire body of a document. It is required in every LaTeX document.  See Starting and ending.

Synopsis:

     \AtBeginDocument{CODE}

Save CODE and execute it when \begin{document} is executed, at the very end of the preamble.  The code is executed after the font selection tables have been set up, so the normal font for the document is the current font.  However, the code is executed as part of the preamble so you cannot do any typesetting with it.

You can issue this command more than once; the successive code lines will be executed in the order that you gave them.

Synopsis:

     \AtEndDocument{CODE}

Save CODE and execute it near the end of the document. Specifically, it is executed when \end{document} is executed, before the final page is finished and before any leftover floating environments are processed. If you want some of the code to be executed after these two processes then include a \clearpage at the appropriate point in CODE.

You can issue this command more than once; the successive code lines will be executed in the order that you gave them.

enumerate
=========

Synopsis:

     \begin{enumerate}
     \item [FIRST LABEL] text of first item
     \item [SECOND LABEL] text of second item
     ...
     \end{enumerate}

Environment to produce a numbered list of items.  The format of the label numbering depends on whether this environment is nested within another; see below.

The list consists of at least one item.  Having no items causes the LaTeX error Something's wrong--perhaps a missing \item.  Each item is produced with an \item command.

This example lists the top two finishers in the 1908 Olympic marathon.

     \begin{enumerate}
      \item Johnny Hayes (USA)
      \item Charles Hefferon (RSA)
     \end{enumerate}

Enumerations may be nested within a paragraph-making environment, including itemize (see itemize), description (see description) and enumeration, up to four levels deep. The format of the label produced depends on the place in the nesting. This gives LaTeX's default for the format at each nesting level (where 1 is the outermost level):

 1. arabic number followed by a period: 1., 2., ...

 2. lower case letter inside parentheses: (a), (b) ...

 3. lower case roman numeral followed by a period: i., ii., ...

 4. upper case letter followed by a period: A., B., ...

The enumerate environment uses the counters \enumi through \enumiv counters (see Counters).  If you use the optional argument to \item then the counter is not incremented for that item (see \item).

To change the format of the label use \renewcommand (see \newcommand & \renewcommand) on the commands \labelenumi through \labelenumiv. For instance, this first level list will be labelled with uppercase letters, in boldface, and without a trailing period:

     \renewcommand{\labelenumi}{\textbf{\Alph{enumi}}}
     \begin{enumerate}
       \item eI
       \item bi:
       \item si:
     \end{enumerate}

For a list of counter-labelling commands like \Alph see \alph \Alph \arabic \roman \Roman \fnsymbol.

For more on customizing the layout see list.  Also, the package enumitem is useful for this.

eqnarray
========

First, a caveat: the eqnarray environment is depreciated.  It has infelicities that cannot be overcome, including spacing that is inconsistent with other mathematics elements (see the article ``Avoid eqnarray!'' by Lars Madsen http://tug.org/TUGboat/tb33-1/tb103madsen.pdf).  New documents should include the amsmath package and use the displayed mathematics environments provided there, such as the align environment.

Nevertheless, for completeness and for a reference when working with old documents, a synopsis:

     \begin{eqnarray}
       FIRST FORMULA LEFT  &FIRST FORMULA MIDDLE  &FIRST FORMULA RIGHT \\
       ...
     \end{eqnarray}

or

     \begin{eqnarray*}
       FIRST FORMULA LEFT  &FIRST FORMULA MIDDLE  &FIRST FORMULA RIGHT \\
       ...
     \end{eqnarray*}

Display a sequence of equations or inequalities.  The left and right sides are typeset in display mode, while the middle is typeset in text mode.

It is similar to a three-column array environment, with items within a row separated by an ampersand (&), and with rows separated by double backslash  \\). The starred form of line break (\\*) can also be used to separate equations, and will disallow a page break there (see \\).

The unstarred form eqnarray places an equation number on every line (using the equation counter), unless that line contains a \nonumber command.  The starred form eqnarray* omits equation numbering, while otherwise being the same.

The command \lefteqn is used for splitting long formulas across lines. It typesets its argument in display style flush left in a box of zero width.

This example shows three lines.  The first two lines make an inequality, while the third line has not entry on the left side.

     \begin{eqnarray*}
       \lefteqn{x_1+x_2+\cdots+x_n}     \\
         &\leq &y_1+y_2+\cdots+y_n      \\
         &=    &z+y_3+\cdots+y_n
     \end{eqnarray*}

equation
========

Synopsis:

     \begin{equation}
       math text
     \end{equation}

Make a displaymath environment (see displaymath) with an equation number in the right margin.

The equation number is generated using the equation counter.

Note that the amsmath package has extensive displayed equation facilities.  Those facilities are the best approach for such output in new documents.

figure
======

Synopsis:

     \begin{figure}[PLACEMENT]
       figure body
     \caption[LOFTITLE]{TITLE}
     \label{LABEL}
     \end{figure}

or

     \begin{figure*}[PLACEMENT]
       figure body
     \caption[LOFTITLE]{TITLE}
     \label{LABEL}
     \end{figure*}

A class of floats (see Floats).  Because they cannot be split across pages, they are not typeset in sequence with the normal text but instead are ``floated'' to a convenient place, such as the top of a following page.

For the possible values of PLACEMENT and their effect on the float placement algorithm, see Floats.

The starred form figure* is used when a document is in double-column mode (see \twocolumn).  It produces a figure that spans both columns, at the top of the page.  To add the possibility of placing at a page bottom see the discussion of PLACEMENT b in Floats.

The figure body is typeset in a parbox of width \textwidth and so it can contain text, commands, etc.

The label is optional; it is used for cross-references (see Cross references). The optional \caption command specifies caption text for the figure.  By default it is numbered.  If LOFTITLE is present, it is used in the list of figures instead of TITLE (see Tables of contents).

This example makes a figure out of a graphic.  It requires one of the packages graphics or graphicx.  The graphic, with its caption, will be placed at the top of a page or, if it is pushed to the end of the document, on a page of floats.

     \begin{figure}[t]
       \centering
       \includegraphics[width=0.5\textwidth]{CTANlion.png}
       \caption{The CTAN lion, by Duane Bibby}
     \end{figure}

filecontents: Write an external file
====================================

Synopsis:

     \begin{filecontents}{FILENAME}
       TEXT
     \end{filecontents}

or

     \begin{filecontents*}{FILENAME}
       TEXT
     \end{filecontents*}

Create a file named FILENAME and fill it with TEXT.  The unstarred version of the environment filecontents prefixes the content of the created file with a header; see the example below.  The starred version filecontents* does not include the header.

This environment can be used anywhere in the preamble, although it often appears before the \documentclass command.  It is typically used when a source file requires a nonstandard style or class file.  The environment will write that file to the directory containing the source and thus make the source file self-contained.  Another use is to include bib references in the file, again to make it self-contained.

The environment checks whether a file of that name already exists and if so, does not do anything.  There is a filecontents package that redefines the filecontents environment so that instead of doing nothing in that case, it will overwrite the existing file.

For example, this document

     \documentclass{article}
     \begin{filecontents}{JH.sty}
     \newcommand{\myname}{Jim Hef{}feron}
     \end{filecontents}
     \usepackage{JH}
     \begin{document}
     Article by \myname.
     \end{document}

produces this file JH.sty.

     %% LaTeX2e file `JH.sty'
     %% generated by the `filecontents' environment
     %% from source `test' on 2015/10/12.
     %%
     \newcommand{\myname}{Jim Hef{}feron}

flushleft
=========

     \begin{flushleft}
     LINE1 \\
     LINE2 \\
     ...
     \end{flushleft}

The flushleft environment allows you to create a paragraph consisting of lines that are flush to the left-hand margin and ragged right. Each line must be terminated with the string \\.

\raggedright
------------

The \raggedright declaration corresponds to the flushleft environment.  This declaration can be used inside an environment such as quote or in a parbox.

Unlike the flushleft environment, the \raggedright command does not start a new paragraph; it only changes how LaTeX formats paragraph units.  To affect a paragraph unit's format, the scope of the declaration must contain the blank line or \end command that ends the paragraph unit.

flushright
==========

     \begin{flushright}
     LINE1 \\
     LINE2 \\
     ...
     \end{flushright}

The flushright environment allows you to create a paragraph consisting of lines that are flush to the right-hand margin and ragged left.  Each line must be terminated with the control sequence \\.

\raggedleft
-----------

The \raggedleft declaration corresponds to the flushright environment.  This declaration can be used inside an environment such as quote or in a parbox.

Unlike the flushright environment, the \raggedleft command does not start a new paragraph; it only changes how LaTeX formats paragraph units.  To affect a paragraph unit's format, the scope of the declaration must contain the blank line or \end command that ends the paragraph unit.

itemize
=======

Synopsis:

     \begin{itemize}
     \item ITEM1
     \item ITEM2
     ...
     \end{itemize}

The itemize environment produces an ``unordered'', ``bulleted'' list.  Itemizations can be nested within one another, up to four levels deep.  They can also be nested within other paragraph-making environments, such as enumerate (see enumerate).

Each item of an itemize list begins with an \item command. There must be at least one \item command within the environment.

By default, the marks at each level look like this:

 1. * (bullet)

 2. -- (bold en-dash)

 3. * (asterisk)

 4. . (centered dot, rendered here as a period)

The itemize environment uses the commands \labelitemi through \labelitemiv to produce the default label.  So, you can use \renewcommand to change the labels.  For instance, to have the first level use diamonds:

     \renewcommand{\labelitemi}{$\diamond$}

The \leftmargini through \leftmarginvi parameters define the distance between the left margin of the enclosing environment and the left margin of the list.  By convention, \leftmargin is set to the appropriate \leftmarginN when a new level of nesting is entered.

The defaults vary from .5em (highest levels of nesting) to 2.5em (first level), and are a bit reduced in two-column mode. This example greatly reduces the margin space for outermost lists:

     \setlength{\leftmargini}{1.25em} % default 2.5em

Some parameters that affect list formatting:

\itemindent
     Extra indentation before each item in a list; default zero.

\labelsep
     Space between the label and text of an item; default .5em.

\labelwidth
     Width of the label; default 2em, or 1.5em in two-column mode.

\listparindent
     Extra indentation added to second and subsequent paragraphs within a list item; default 0pt.

\rightmargin
     Horizontal distance between the right margin of the list and the enclosing environment; default 0pt, except in the quote, quotation, and verse environments, where it is set equal to \leftmargin.

Parameters affecting vertical spacing between list items (rather loose, by default).

\itemsep
     Vertical space between items.  The default is 2pt plus1pt minus1pt for 10pt documents, 3pt plus2pt minus1pt for 11pt, and 4.5pt plus2pt minus1pt for 12pt.

\parsep
     Extra vertical space between paragraphs within a list item.  Defaults are the same as \itemsep.

\topsep
     Vertical space between the first item and the preceding paragraph. For top-level lists, the default is 8pt plus2pt minus4pt for 10pt documents, 9pt plus3pt minus5pt for 11pt, and 10pt plus4pt minus6pt for 12pt.  These are reduced for nested lists.

\partopsep
     Extra space added to \topsep when the list environment starts a paragraph.  The default is 2pt plus1pt minus1pt for 10pt documents, 3pt plus1pt minus1pt for 11pt, and 3pt plus2pt minus2pt for 12pt.

Especially for lists with short items, it may be desirable to elide space between items.  Here is an example defining an itemize* environment with no extra spacing between items, or between paragraphs within a single item (\parskip is not list-specific, see \parskip):

     \newenvironment{itemize*}%
       {\begin{itemize}%
         \setlength{\itemsep}{0pt}%
         \setlength{\parsep}{0pt}}%
         \setlength{\parskip}{0pt}}%
       {\end{itemize}}

letter environment: writing letters
===================================

This environment is used for creating letters.  See Letters.

list
====

The list environment is a generic environment which is used for defining many of the more specific environments. It is seldom used in documents, but often in macros.

     \begin{list}{LABELING}{SPACING}
     \item ITEM1
     \item ITEM2
     ...
     \end{list}

The mandatory LABELING argument specifies how items should be labelled (unless the optional argument is supplied to \item). This argument is a piece of text that is inserted in a box to form the label.  It can and usually does contain other LaTeX commands.

The mandatory SPACING argument contains commands to change the spacing parameters for the list.  This argument will most often be empty, i.e., {}, which leaves the default spacing.

The width used for typesetting the list items is specified by \linewidth (see Page layout parameters).

Synopsis:

     \item text of item

or

     \item[OPTIONAL LABEL] text of item

An entry in a list.  The entries are prefixed by a label, whose default depends on the list type.

Because the optional argument OPTIONAL LABEL is surrounded by square brackets ([ and ]), to use square brackets inside the optional argument you must hide them inside curly braces, as in \item[Close square bracket, {]}].  Similarly, to use an open square bracket as first character in the text of the item, also hide it inside curly braces.  See LaTeX command syntax.

In this example the enumerate list has two items that use the default label and one that uses the optional label.

     \begin{enumerate}
       \item Moe
       \item[sometimes] Shemp
       \item Larry
     \end{enumerate}

The first item is labelled 1., the second item is labelled sometimes, and the third item is labelled 2. (note that, because of the optional label in the second item, the third item does not get a 3.).

math
====

Synopsis:

     \begin{math}
     MATH
     \end{math}

The math environment inserts the given MATH within the running text.  \(...\) and $...$ are synonyms. See Math formulas.

minipage
========

     \begin{minipage}[POSITION][HEIGHT][INNER-POS]{WIDTH}
     TEXT
     \end{minipage}

The minipage environment typesets its body TEXT in a block that will not be broken across pages.  This is similar to the \parbox command (see \parbox), but unlike \parbox, other paragraph-making environments can be used inside a minipage.

The arguments are the same as for \parbox (see \parbox).

By default, paragraphs are not indented in the minipage environment.  You can restore indentation with a command such as \setlength{\parindent}{1pc} command.

Footnotes in a minipage environment are handled in a way that is particularly useful for putting footnotes in figures or tables.  A \footnote or \footnotetext command puts the footnote at the bottom of the minipage instead of at the bottom of the page, and it uses the \mpfootnote counter instead of the ordinary footnote counter (see Counters).

However, don't put one minipage inside another if you are using footnotes; they may wind up at the bottom of the wrong minipage.

picture
=======

     \begin{picture}(WIDTH,HEIGHT)(XOFFSET,YOFFSET)
     ... PICTURE COMMANDS ...
     \end{picture}

The picture environment allows you to create just about any kind of picture you want containing text, lines, arrows and circles. You tell LaTeX where to put things in the picture by specifying their coordinates.  A coordinate is a number that may have a decimal point and a minus sign---a number like 5, 0.3 or -3.1416.  A coordinate specifies a length in multiples of the unit length \unitlength, so if \unitlength has been set to 1cm, then the coordinate 2.54 specifies a length of 2.54 centimeters.

You should only change the value of \unitlength, using the \setlength command, outside of a picture environment. The default value is 1pt.

A position is a pair of coordinates, such as (2.4,-5), specifying the point with x-coordinate 2.4 and y-coordinate -5. Coordinates are specified in the usual way with respect to an origin, which is normally at the lower-left corner of the picture.  Note that when a position appears as an argument, it is not enclosed in braces; the parentheses serve to delimit the argument.

The picture environment has one mandatory argument which is a position (WIDTH,HEIGHT), which specifies the size of the picture.  The environment produces a rectangular box with these WIDTH and HEIGHT.

The picture environment also has an optional position argument (XOFFSET,YOFFSET), following the size argument, that can change the origin.  (Unlike ordinary optional arguments, this argument is not contained in square brackets.) The optional argument gives the coordinates of the point at the lower-left corner of the picture (thereby determining the origin).  For example, if \unitlength has been set to 1mm, the command

     \begin{picture}(100,200)(10,20)

produces a picture of width 100 millimeters and height 200 millimeters, whose lower-left corner is the point (10,20) and whose upper-right corner is therefore the point (110,220).  When you first draw a picture, you typically omit the optional argument, leaving the origin at the lower-left corner.  If you then want to modify your picture by shifting everything, you can just add the appropriate optional argument.

The environment's mandatory argument determines the nominal size of the picture.  This need bear no relation to how large the picture really is; LaTeX will happily allow you to put things outside the picture, or even off the page.  The picture's nominal size is used by LaTeX in determining how much room to leave for it.

Everything that appears in a picture is drawn by the \put command. The command

     \put (11.3,-.3){...}

puts the object specified by ... in the picture, with its reference point at coordinates (11.3,-.3). The reference points for various objects will be described below.

The \put command creates an LR box.  You can put anything that can go in an \mbox (see \mbox) in the text argument of the \put command.  When you do this, the reference point will be the lower left corner of the box.

The picture commands are described in the following sections.

\circle
-------

Synopsis:

     \circle[*]{DIAMETER}

The \circle command produces a circle with a diameter as close to the specified one as possible.  The *-form of the command draws a solid circle.

Circles up to 40pt can be drawn.

\makebox
--------

Synopsis:

     \makebox(WIDTH,HEIGHT)[POSITION]{TEXT}

The \makebox command for the picture environment is similar to the normal \makebox command except that you must specify a WIDTH and HEIGHT in multiples of \unitlength.

The optional argument, [POSITION], specifies the quadrant that your TEXT appears in.  You may select up to two of the following:

t
     Moves the item to the top of the rectangle.

b
     Moves the item to the bottom.

l
     Moves the item to the left.

r
     Moves the item to the right.

See \makebox.

\framebox
---------

Synopsis:

     \framebox(WIDTH,HEIGHT)[POS]{...}

The \framebox command is like \makebox (see previous section), except that it puts a frame around the outside of the box that it creates.

The \framebox command produces a rule of thickness \fboxrule, and leaves a space \fboxsep between the rule and the contents of the box.

\dashbox
--------

Draws a box with a dashed line.  Synopsis:

     \dashbox{DLEN}(RWIDTH,RHEIGHT)[POS]{TEXT}

\dashbox creates a dashed rectangle around TEXT in a picture environment.  Dashes are DLEN units long, and the rectangle has overall width RWIDTH and height RHEIGHT. The TEXT is positioned at optional POS.

A dashed box looks best when the RWIDTH and RHEIGHT are multiples of the DLEN.

\frame
------

Synopsis:

     \frame{TEXT}

The \frame command puts a rectangular frame around TEXT. The reference point is the bottom left corner of the frame.  No extra space is put between the frame and the object.

\line
-----

Synopsis:

     \line(XSLOPE,YSLOPE){LENGTH}

The \line command draws a line with the given LENGTH and slope XSLOPE/YSLOPE.

Standard LaTeX can only draw lines with SLOPE = x/y, where x and y have integer values from -6 through 6.  For lines of any slope, and plenty of other shapes, see pict2e and many other packages on CTAN.

\linethickness
--------------

The \linethickness{DIM} command declares the thickness of horizontal and vertical lines in a picture environment to be DIM, which must be a positive length.

\linethickness does not affect the thickness of slanted lines, circles, or the quarter circles drawn by \oval.

\thicklines
-----------

The \thicklines command is an alternate line thickness for horizontal and vertical lines in a picture environment; cf. \linethickness and \thinlines.

\thinlines
----------

The \thinlines command is the default line thickness for horizontal and vertical lines in a picture environment; cf. \linethickness and \thicklines.

\multiput
---------

Synopsis:

     \multiput(X,Y)(DELTA_X,DELTA_Y){N}{OBJ}

The \multiput command copies the object OBJ in a regular pattern across a picture.  OBJ is first placed at position (x,y), then at (x+\delta x,y+\delta y), and so on, N times.

\oval
-----

Synopsis:

     \oval(WIDTH,HEIGHT)[PORTION]

The \oval command produces a rectangle with rounded corners.  The optional argument PORTION allows you to produce only half of the oval via the following:

t
     selects the top half;

b
     selects the bottom half;

r
     selects the right half;

l
     selects the left half.

It is also possible to produce only one quarter of the oval by setting PORTION to tr, br, bl, or tl.

The ``corners'' of the oval are made with quarter circles with a maximum radius of 20pt, so large ``ovals'' will look more like boxes with rounded corners.

\put
----

Synopsis:

     \put(XCOORD,YCOORD){ ... }

The \put command places the material specified by the (mandatory) argument in braces at the given coordinate, (XCOORD,YCOORD).

\shortstack
-----------

Synopsis:

     \shortstack[POSITION]{...\\...\\...}

The \shortstack command produces a stack of objects.  The valid positions are:

r
     Move the objects to the right of the stack.

l
     Move the objects to the left of the stack

c
     Move the objects to the centre of the stack (default)

Objects are separated with \\.

\vector
-------

Synopsis:

     \vector(XSLOPE,YSLOPE){LENGTH}

The \vector command draws a line with an arrow of the specified length and slope.  The XSLOPE and YSLOPE values must lie between -4 and +4, inclusive.

quotation and quote
===================

Synopsis:

     \begin{quotation}
     TEXT
     \end{quotation}

or

     \begin{quote}
     TEXT
     \end{quote}

Include a quotation.

In both environments, margins are indented on both sides by \leftmargin and the text is justified at both.  As with the main text, leaving a blank line produces a new paragraph.

To compare the two: in the quotation environment, paragraphs are indented by 1.5em and the space between paragraphs is small, 0pt plus 1pt.  In the quote environment, paragraphs are not indented and there is vertical space between paragraphs (it is the rubber length \parsep).  Thus, the quotation environment may be more suitable for documents where new paragraphs are marked by an indent rather than by a vertical separation.  In addition, quote may be more suitable for a short quotation or a sequence of short quotations.

     \begin{quotation}
     \it Four score and seven years ago
       .. shall not perish from the earth.
     \hspace{1em plus 1fill}---Abraham Lincoln
     \end{quotation}

tabbing
=======

Synopsis:

     \begin{tabbing}
     ROW1COL1 \= ROW1COL2 \= ROW1COL3 \= ROW1COL4 \\
     ROW2COL1 \>                \> ROW2COL3 \\
     ...
     \end{tabbing}

The tabbing environment provides a way to align text in columns.  It works by setting tab stops and tabbing to them much as was done on an ordinary typewriter.  It is best suited for cases where the width of each column is constant and known in advance.

This environment can be broken across pages, unlike the tabular environment.

The following commands can be used inside a tabbing environment:

\\ (tabbing)
     End a line.

\= (tabbing)
     Sets a tab stop at the current position.

\> (tabbing)
     Advances to the next tab stop.

\<
     Put following text to the left of the local margin (without changing the margin).  Can only be used at the start of the line.

\+
     Moves the left margin of the next and all the following commands one tab stop to the right, beginning tabbed line if necessary.

\-
     Moves the left margin of the next and all the following commands one tab stop to the left, beginning tabbed line if necessary.

\' (tabbing)
     Moves everything that you have typed so far in the current column, i.e., everything from the most recent \>, \<, \', \\, or \kill command, to the right of the previous column, flush against the current column's tab stop.

\` (tabbing)
     Allows you to put text flush right against any tab stop, including tab stop 0.  However, it can't move text to the right of the last column because there's no tab stop there.  The \` command moves all the text that follows it, up to the \\ or \end{tabbing} command that ends the line, to the right margin of the tabbing environment.  There must be no \> or \' command between the \` and the command that ends the line.

\a (tabbing)
     In a tabbing environment, the commands \=, \' and \` do not produce accents as usual (see Accents).  Instead, the commands \a=, \a' and \a` are used.

\kill
     Sets tab stops without producing text.  Works just like \\ except that it throws away the current line instead of producing output for it.  The effect of any \=, \+ or \- commands in that line remain in effect.

\poptabs
     Restores the tab stop positions saved by the last \pushtabs.

\pushtabs
     Saves all current tab stop positions. Useful for temporarily changing tab stop positions in the middle of a tabbing environment.

\tabbingsep
     Distance to left of tab stop moved by \'.

This example typesets a Pascal function in a traditional format:

     \begin{tabbing}
     function \= fact(n : integer) : integer;\\
              \> begin \= \+ \\
                    \> if \= n $>$ 1 then \+ \\
                             fact := n * fact(n-1) \- \\
                       else \+ \\
                             fact := 1; \-\- \\
                 end;\\
     \end{tabbing}

table
=====

Synopsis:

     \begin{table}[PLACEMENT]
       table body
     \caption[LOFTITLE]{TITLE}
     \label{LABEL}
     \end{table}

A class of floats (see Floats).  Because they cannot be split across pages, they are not typeset in sequence with the normal text but instead are ``floated'' to a convenient place, such as the top of a following page.

For the possible values of PLACEMENT and their effect on the float placement algorithm, see Floats.

The table body is typeset in a parbox of width \textwidth and so it can contain text, commands, etc.

The label is optional; it is used for cross-references (see Cross references). The optional \caption command specifies caption text for the table.  By default it is numbered.  If LOTTITLE is present, it is used in the list of tables instead of TITLE (see Tables of contents).

In this example the table and caption will float to the bottom of a page, unless it is pushed to a float page at the end.

     \begin{table}[b]
       \centering
       \begin{tabular}{r|p{2in}} \hline
         One &The loneliest number \\
         Two &Can be as sad as one.
              It's the loneliest number since the number one.
       \end{tabular}
       \caption{Cardinal virtues}
       \label{tab:CardinalVirtues}
     \end{table}

tabular
=======

Synopsis:

     \begin{tabular}[POS]{COLS}
     column 1 entry &column 2 entry ... &column n entry \\
       ...
     \end{tabular}

or

     \begin{tabular*}{WIDTH}[POS]{COLS}
     column 1 entry &column 2 entry ... &column n entry \\
       ...
     \end{tabular*}

These environments produce a table, a box consisting of a sequence of horizontal rows.  Each row consists of items that are aligned vertically in columns.  This illustrates many of the features.

     \begin{tabular}{l|l}
       \textit{Player name}  &\textit{Career home runs}  \\
       \hline
       Hank Aaron  &755 \\
       Babe Ruth   &714
     \end{tabular}

The vertical format of two left-aligned columns, with a vertical bar between them, is specified in tabular's argument {l|l}. Columns are separated with an ampersand &.  A horizontal rule between two rows is created with \hline. The end of each row is marked with a double backslash \\. This \\ is optional after the last row unless an \hline command follows, to put a rule below the table.

The required and optional arguments to tabular consist of:

width
     Required for tabular*, not allowed for tabular. Specifies the width of the tabular* environment.  The space between columns should be rubber, as with @{\extracolsep{\fill}}, to allow the table to stretch or shrink to make the specified width, or else you are likely to get the Underfull \hbox (badness 10000) in alignment ..  warning.

pos
     Optional.  Specifies the table's vertical position.  The default is to align the table so its vertical center matches the baseline of the surrounding text.  There are two other possible alignments: t aligns the table so its top row matches the baseline of the surrounding text, and b aligns on the bottom row.

     This only has an effect if there is other text.  In the common case of a tabular alone in a center environment this option makes no difference.

cols
     Required.  Specifies the formatting of columns.  It consists of a sequence of the following specifiers, corresponding to the types of column and intercolumn material.

     l
          A column of left-aligned items.

     r
          A column of right-aligned items.

     c
          A column of centered items.

     |
          A vertical line the full height and depth of the environment.

     @{TEXT OR SPACE}
          This inserts TEXT OR SPACE at this location in every row.  The TEXT OR SPACE material is typeset in LR mode.  This text is fragile (see \protect).

          This specifier is optional: unless you put in your own @-expression then LaTeX's book, article, and report classes will put on either side of each column a space of length \tabcolsep, which by default is 6pt.  That is, by default adjacent columns are separated by 12pt (so \tabcolsep is misleadingly-named since it is not the separation between tabular columns).  Also by default a space of 6pt comes before the first column as well as after the final column, unless you put a @{..} or | there.

          If you override the default and use an @-expression then you must insert any desired space yourself, as in @{\hspace{1em}}.

          An empty expression @{} will eliminate the space, including the space at the start or end, as in the example below where the tabular lines need to lie on the left margin.

               \begin{flushleft}
                 \begin{tabular}{@{}l}
                   ..
                 \end{tabular}
               \end{flushleft}

          This example shows text, a decimal point, between the columns, arranged so the numbers in the table are aligned on that decimal point.

               \begin{tabular}{r@{$.$}l}
                 $3$ &$14$  \\
                 $9$ &$80665$
               \end{tabular}

          An \extracolsep{WD} command in an @-expression causes an extra space of width WD to appear to the left of all subsequent columns, until countermanded by another \extracolsep command. Unlike ordinary intercolumn space, this extra space is not suppressed by an @-expression.  An \extracolsep command can be used only in an @-expression in the cols argument.  Below, LaTeX inserts the right amount of intercolumn space to make the entire table 4 inches wide.

               \begin{center}
                 \begin{tabular*}{4in}{l@{\ \ldots\extracolsep{\fill}}l}
                   Seven times down, eight times up
                   &such is life!
                 \end{tabular*}
               \end{center}

          To insert commands that are automatically executed before a given column, load the array package and use the >{...} specifier.

     p{WD}
          Each item in the column is typeset in a parbox of width WD.

          Note that a line break double backslash \\ may not appear in the item, except inside an environment like minipage, array, or tabular, or inside an explicit \parbox, or in the scope of a \centering, \raggedright, or \raggedleft declaration (when used in a p-column element these declarations must appear inside braces, as with {\centering .. \\ ..}). Otherwise LaTeX will misinterpret the double backslash as ending the row.

     *{NUM}{COLS}
          Equivalent to NUM copies of COLS, where NUM is a positive integer and COLS is a list of specifiers.  Thus \begin{tabular}{|*{3}{l|r}|} is equivalent to \begin{tabular}{|l|rl|rl|r|}.  Note that COLS may contain another *-expression.

Parameters that control formatting:

\arrayrulewidth
     A length that is the thickness of the rule created by |, \hline, and \vline in the tabular and array environments.  The default is .4pt. Change it as in \setlength{\arrayrulewidth}{0.8pt}.

\arraystretch
     A factor by which the spacing between rows in the tabular and array environments is multiplied.  The default is 1, for no scaling.  Change it as \renewcommand{\arraystretch}{1.2}.

\doublerulesep
     A length that is the distance between the vertical rules produced by the || specifier.  The default is 2pt.

\tabcolsep
     A length that is half of the space between columns. The default is 6pt.  Change it with \setlength.

The following commands can be used inside the body of a tabular environment, the first two inside an entry and the second two between lines:

\multicolumn
------------

Synopsis:

     \multicolumn{NUMCOLS}{COLS}{TEXT}

Make an array or tabular entry that spans several columns. The first argument NUMCOLS gives the number of columns to span. The second argument COLS specifies the formatting of the entry, with c for centered, l for flush left, or r for flush right.  The third argument TEXT gives the contents of that entry.

In this example, in the first row, the second and third columns are spanned by the single heading Name.

     \begin{tabular}{lccl}
       \textit{ID}       &\multicolumn{2}{c}{\textit{Name}} &\textit{Age} \\ \hline % row one
       978-0-393-03701-2 &O'Brian &Patrick                  &55           \\        % row two
         ..
     \end{tabular}

What counts as a column is: the column format specifier for the array or tabular environment is broken into parts, where each part (except the first) begins with l, c, r, or p.  So from \begin{tabular}{|r|ccp{1.5in}|} the parts are |r|, c, c, and p{1.5in}|.

The COLS argument overrides the array or tabular environment's intercolumn area default adjoining this multicolumn entry. To affect that area, this argument can contain vertical bars | indicating the placement of vertical rules, and @{..} expressions.  Thus if COLS is |c| then this multicolumn entry will be centered and a vertical rule will come in the intercolumn area before it and after it.  This table details the exact behavior.

     \begin{tabular}{|cc|c|c|}
       \multicolumn{1}{r}{w}       % entry one
         &\multicolumn{1}{|r|}{x}  % entry two
         &\multicolumn{1}{|r}{y}   % entry three
         &z                        % entry four
     \end{tabular}

Before the first entry the output will not have a vertical rule because the \multicolumn has the COLS specifier r with no initial vertical bar.  Between entry one and entry two there will be a vertical rule; although the first COLS does not have an ending vertical bar, the second COLS does have a starting one.  Between entry two and entry three there is a single vertical rule; despite that the COLS in both of the surrounding multicolumn's call for a vertical rule, you only get one rule.  Between entry three and entry four there is no vertical rule; the default calls for one but the COLS in the entry three \multicolumn leaves it out, and that takes precedence.  Finally, following entry four there is a vertical rule because of the default.

The number of spanned columns NUMCOLS can be 1.  Besides giving the ability to change the horizontal alignment, this also is useful to override for one row the tabular definition's default intercolumn area specification, including the placement of vertical rules.

In the example below, in the tabular definition the first column is specified to default to left justified but in the first row the entry is centered with \multicolumn{1}{c}{\textsc{Period}}. Also in the first row, the second and third columns are spanned by a single entry with \multicolumn{2}{c}{\textsc{Span}}, overriding the specification to center those two columns on the page range en-dash.

     \begin{tabular}{l|r@{--}l}
       \multicolumn{1}{c}{\textsc{Period}}
         &multicolumn{2}{c}{\textsc{Span}} \\ \hline
       Baroque          &1600           &1760         \\
       Classical        &1730           &1820         \\
       Romantic         &1780           &1910         \\
       Impressionistic  &1875           &1925
     \end{tabular}

Note that although the tabular specification by default puts a vertical rule between the first and second columns, because there is no vertical bar in the COLS of either of the first row's \multicolumn commands, no rule appears in the first row.

\vline
------

Draw a vertical line in a tabular or array environment extending the full height and depth of an entry's row.  Can also be used in an @-expression, although its synonym vertical bar | is more common.  This command is rarely used; typically a table's vertical lines are specified in tabular's COLS argument and overriden as needed with \multicolumn.

This example illustrates some pitfalls.  In the first line's second entry the \hfill moves the \vline to the left edge of the cell.  But that is different than putting it halfway between the two columns, so in that row between the first and second columns there are two vertical rules, with the one from the {c|cc} specifier coming before the one produced by the \vline\hfill.  In contrast, the first line's third entry shows the usual way to put a vertical bar between two columns.  In the second line, the ghi is the widest entry in its column so in the \vline\hfill the \hfill has no effect and the vertical line in that entry appears immediately next to the g, with no whitespace.

     \begin{tabular}{c|cc}
       x   &\vline\hfill y   &\multicolumn{1}{|r}{z} \\
       abc &def &\vline\hfill ghi
     \end{tabular}

\cline
------

Synopsis:

     \cline{I-J}

Draw a horizontal rule in an array or tabular environment beginning in column I and ending in column J. The dash - must appear in the mandatory argument. To span a single column use the number twice.

This example puts two horizontal lines between the first and second rows, one line in the first column only, and the other spanning the third and fourth columns.  The two lines are side-by-side, at the same height.

     \begin{tabular}{llrr}
       a &b &c &d \\ \cline{1-1} \cline{3-4}
       e &f &g &h
     \end{tabular}

\hline
------

Draws a horizontal line the width of the enclosing tabular or array environment.  It's most commonly used to draw a line at the top, bottom, and between the rows of a table.

In this example the top of the table has two horizontal rules, one above the other, that span both columns.  The bottom of the table has a single rule spanning both columns.  Because of the \hline, the tabular second row's line ending double backslash \\ is required.

     \begin{tabular}{ll} \hline\hline
       Baseball   &Red Sox  \\
       Basketball &Celtics  \\ \hline
     \end{tabular}

thebibliography
===============

Synopsis:

     \begin{thebibliography}{WIDEST-LABEL}
     \bibitem[LABEL]{CITE_KEY}
     ...
     \end{thebibliography}

The thebibliography environment produces a bibliography or reference list.

In the article class, this reference list is labelled ``References''; in the report class, it is labelled ``Bibliography''.  You can change the label (in the standard classes) by redefining the command \refname.  For instance, this eliminates it entirely:

     \renewcommand{\refname}{}

The mandatory WIDEST-LABEL argument is text that, when typeset, is as wide as the widest item label produced by the \bibitem commands.  It is typically given as 9 for bibliographies with less than 10 references, 99 for ones with less than 100, etc.

\bibitem
--------

Synopsis:

     \bibitem[LABEL]{CITE_KEY}

The \bibitem command generates an entry labelled by LABEL.  If the LABEL argument is missing, a number is automatically generated using the enumi counter.  The CITE_KEY is any sequence of letters, numbers, and punctuation symbols not containing a comma.

This command writes an entry to the .aux file containing the item's CITE_KEY and label.  When the .aux file is read by the \begin{document} command, the item's label is associated with cite_key, causing references to CITE_KEY with a \cite command (see next section) to produce the associated label.

\cite
-----

Synopsis:

     \cite[SUBCITE]{KEYS}

The KEYS argument is a list of one or more citation keys, separated by commas.  This command generates an in-text citation to the references associated with KEYS by entries in the .aux file.

The text of the optional SUBCITE argument appears after the citation.  For example, \cite[p.~314]{knuth} might produce `[Knuth, p. 314]'.

\nocite
-------

\nocite{KEYS}

The \nocite command produces no text, but writes KEYS, which is a list of one or more citation keys, to the .aux file.

Using BibTeX
------------

If you use the BibTeX program by Oren Patashnik (highly recommended if you need a bibliography of more than a couple of titles) to maintain your bibliography, you don't use the thebibliography environment (see thebibliography). Instead, you include the lines

     \bibliographystyle{BIBSTYLE}
     \bibliography{BIBFILE1,BIBFILE2}

The \bibliographystyle command does not produce any output of its own.  Rather, it defines the style in which the bibliography will be produced: BIBSTYLE refers to a file BIBSTYLE.bst, which defines how your citations will look. The standard STYLE names distributed with BibTeX are:

alpha
     Sorted alphabetically. Labels are formed from name of author and year of publication.

plain
     Sorted alphabetically. Labels are numeric.

unsrt
     Like plain, but entries are in order of citation.

abbrv
     Like plain, but more compact labels.

In addition, numerous other BibTeX style files exist tailored to the demands of various publications.  See http://mirror.ctan.org/biblio/bibtex/contrib.

The \bibliography command is what actually produces the bibliography.  The argument to \bibliography refers to files named BIBFILE.bib, which should contain your database in BibTeX format.  Only the entries referred to via \cite and \nocite will be listed in the bibliography.

theorem
=======

Synopsis:

     \begin{theorem}
     THEOREM-TEXT
     \end{theorem}

The theorem environment produces ``Theorem N'' in boldface followed by THEOREM-TEXT, where the numbering possibilities for N are described under \newtheorem (see \newtheorem).

titlepage
=========

Synopsis:

     \begin{titlepage}
     TEXT
     \end{titlepage}

The titlepage environment creates a title page, i.e., a page with no printed page number or heading.  It also causes the following page to be numbered page one.  Formatting the title page is left to you.  The \today command may be useful on title pages (see \today).

You can use the \maketitle command (see \maketitle) to produce a standard title page without a titlepage environment.

verbatim
========

Synopsis:

     \begin{verbatim}
     LITERAL-TEXT
     \end{verbatim}

The verbatim environment is a paragraph-making environment in which LaTeX produces exactly what you type in; for instance the \ character produces a printed \.  It turns LaTeX into a typewriter with carriage returns and blanks having the same effect that they would on a typewriter.

The verbatim uses a monospaced typewriter-like font (\tt).

\verb
-----

Synopsis:

     \verbCHARLITERAL-TEXTCHAR
     \verb*CHARLITERAL-TEXTCHAR

The \verb command typesets LITERAL-TEXT as it is input, including special characters and spaces, using the typewriter (\tt) font.  No spaces are allowed between \verb or \verb* and the delimiter CHAR, which begins and ends the verbatim text.  The delimiter must not appear in LITERAL-TEXT.

The *-form differs only in that spaces are printed with a ``visible space'' character.

verse
=====

Synopsis:

     \begin{verse}
     LINE1 \\
     LINE2 \\
     ...
     \end{verse}

The verse environment is designed for poetry, though you may find other uses for it.

The margins are indented on the left and the right, paragraphs are not indented, and the text is not justified.  Separate the lines of each stanza with \\, and use one or more blank lines to separate the stanzas.

Line breaking
*************

The first thing LaTeX does when processing ordinary text is to translate your input file into a sequence of glyphs and spaces.  To produce a printed document, this sequence must be broken into lines (and these lines must be broken into pages).

LaTeX usually does the line (and page) breaking in the text body for you but in some environments you manually force line breaks.

\\
==

Synopsis:

     \\[MORESPACE]

or

     \\*[MORESPACE]

Start a new line.  The optional argument MORESPACE specifies extra vertical space to be insert before the next line.  This can be a negative length.  The text before the break is set at its normal length, that is, it is not stretched to fill out the line width.

Explicit line breaks in the text body are unusual in LaTeX.  In particular, to start a new paragraph instead leave a blank line.  This command is mostly used outside of the main flow of text such as in a tabular or array environment.

Under ordinary circumstances (e.g., outside of a p{..} column in a tabular environment) the \newline command is a synonym for \\ (see \newline).

In addition to starting a new line, the starred form \\* tells LaTeX not to start a new page between the two lines, by issuing a \nobreak.

     \title{My story: \\[0.25in]
            a tale of woe}

\obeycr & \restorecr
====================

The \obeycr command makes a return in the input file (^^M, internally) the same as \\ (followed by \relax).  So each new line in the input will also be a new line in the output.

\restorecr restores normal line-breaking behavior.

\newline
========

In ordinary text this is equivalent to double-backslash (see \\); it breaks a line, with no stretching of the text before it.

Inside a tabular or array environment, in a column with a specifier producing a paragraph box, like typically p{..}, \newline will insert a line break inside of the column, that is, it does not break the entire row.  To break the entire row use \\ or its equivalent \tabularnewline.

This will print Name: and Address: as two lines in a single cell of the table.

     \begin{tabular}{p{1in}{\hspace{2in}}p{1in}}
       Name: \newline Address: &Date: \\ \hline
     \end{tabular}

The Date: will be baseline-aligned with Name:.

\- (discretionary hyphen)
=========================

The \- command tells LaTeX that it may hyphenate the word at that point.  LaTeX is pretty good at hyphenating, and usually finds most of the correct hyphenation points, while almost never using an incorrect one.  The \- command is used for the exceptional cases.

When you insert \- commands in a word, the word will only be hyphenated at those points and not at any of the hyphenation points that LaTeX might otherwise have chosen.

\fussy
======

The declaration \fussy (which is the default) makes TeX picky about line breaking.  This usually avoids too much space between words, at the cost of an occasional overfull box.

This command cancels the effect of a previous \sloppy command (see \sloppy.

\sloppy
=======

The declaration \sloppy makes TeX less fussy about line breaking. This will avoid overfull boxes, at the cost of loose interword spacing.

Lasts until a \fussy command is issued (see \fussy).

\hyphenation
============

Synopsis:

     \hyphenation{WORD-ONE WORD-TWO}

The \hyphenation command declares allowed hyphenation points with a - character in the given words.  The words are separated by spaces.  TeX will only hyphenate if the word matches exactly, no inflections are tried.  Multiple \hyphenation commands accumulate.  Some examples (the default TeX hyphenation patterns misses the hyphenations in these words):

     \hyphenation{ap-pen-dix col-umns data-base data-bases}

\linebreak & \nolinebreak
=========================

Synopses:

     \linebreak[PRIORITY]
     \nolinebreak[PRIORITY]

By default, the \linebreak (\nolinebreak) command forces (prevents) a line break at the current position.  For \linebreak, the spaces in the line are stretched out so that it extends to the right margin as usual.

With the optional argument PRIORITY, you can convert the command from a demand to a request.  The PRIORITY must be a number from 0 to 4.  The higher the number, the more insistent the request.

Page breaking
*************

LaTeX starts new pages asynchronously, when enough material has accumulated to fill up a page.  Usually this happens automatically, but sometimes you may want to influence the breaks.

\cleardoublepage
================

The \cleardoublepage command ends the current page and causes all the pending floating figures and tables that have so far appeared in the input to be printed.  In a two-sided printing style, it also makes the next page a right-hand (odd-numbered) page, producing a blank page if necessary.

\clearpage
==========

The \clearpage command ends the current page and causes all the pending floating figures and tables that have so far appeared in the input to be printed.

\newpage
========

The \newpage command ends the current page, but does not clear floats (see \clearpage).

\enlargethispage
================

\enlargethispage{size}

\enlargethispage*{size}

Enlarge the \textheight for the current page by the specified amount; e.g., \enlargethispage{\baselineskip} will allow one additional line.

The starred form tries to squeeze the material together on the page as much as possible. This is normally used together with an explicit \pagebreak.

\pagebreak & \nopagebreak
=========================

Synopses:

     \pagebreak[PRIORITY]
     \nopagebreak[PRIORITY]

By default, the \pagebreak (\nopagebreak) command forces (prevents) a page break at the current position.  With \pagebreak, the vertical space on the page is stretched out where possible so that it extends to the normal bottom margin.

With the optional argument PRIORITY, you can convert the \pagebreak command from a demand to a request.  The number must be a number from 0 to 4.  The higher the number, the more insistent the request is.

Footnotes
*********

Place a numbered footnote at the bottom of the current page, as here.

     Noël Coward quipped that having to read a footnote is like having
     to go downstairs to answer the door, while in the midst of making
     love.\footnote{I wouldn't know, I don't read footnotes.}

You can place multiple footnotes on a page. If the text becomes too long it will flow to the next page.

You can also produce footnotes by combining the \footnotemark and the \footnotetext commands, which is useful in special circumstances.

To make bibliographic references come out as footnotes you need to include a bibliographic style with that behavior.

\footnote
=========

Synopsis:

     \footnote[NUMBER]{TEXT}

Place a numbered footnote TEXT at the bottom of the current page.

     There are over a thousand footnotes in Gibbon's
     \textit{Decline and Fall of the Roman Empire}.\footnote{After
     reading an early version with endnotes David Hume complained,
     ``One is also plagued with his Notes, according to the present Method
     of printing the Book'' and suggested that they ``only to be printed
     at the Margin or the Bottom of the Page.''}

The optional argument NUMBER allows you to specify the footnote number.  If you use this option then the footnote number counter is not incremented, and if you do not use it then the counter is incremented.

Change how LaTeX shows the footnote counter with something like \renewcommand{\thefootnote}{\fnsymbol{footnote}}, which uses a sequence of symbols (see \alph \Alph \arabic \roman \Roman \fnsymbol).  To make this change global put that in the preamble.  If you make the change local then you may want to reset the counter with \setcounter{footnote}{0}.  By default LaTeX uses arabic numbers.

LaTeX's default puts many restrictions on where you can use a \footnote; for instance, you cannot use it in an argument to a sectioning command such as \chapter (it can only be used in outer paragraph mode).  There are some workarounds; see following sections.

In a minipage environment the \footnote command uses the mpfootnote counter instead of the footnote counter, so they are numbered independently.  They are shown at the bottom of the environment, not at the bottom of the page. And by default they are shown alphabetically. See minipage.

\footnotemark
=============

Synopsis, one of:

     \footnotemark
     \footnotemark[NUMBER]

Put the current footnote number in the text. (See \footnotetext for giving the text of the footnote separately.)  The version with the optional argument NUMBER uses that number to determine the mark printed. This command can be used in inner paragraph mode.

This example gives the same institutional affiliation to both the first and third authors (\thanks is a version of footnote).

     \title{A Treatise on the Binomial Theorem}
     \author{J Moriarty\thanks{University of Leeds}
       \and A C Doyle\thanks{Durham University}
       \and S Holmes\footnotemark[1]}
     \begin{document}
     \maketitle

If you use \footnotemark without the optional argument then it increments the footnote counter but if you use the optional NUMBER then it does not. This produces several consecutive footnote markers referring to the same footnote.

     The first theorem\footnote{Due to Gauss.}
     and the second theorem\footnotemark[\value{footnote}]
     and the third theorem.\footnotemark[\value{footnote}]

\footnotetext
=============

Synopsis, one of:

     \footnotetext{TEXT}
     \footnotetext[NUMBER]{TEXT}

Place TEXT at the bottom of the page as a footnote.  This command can come anywhere after the \footnotemark command.  The optional argument NUMBER changes the displayed footnote number.  The \footnotetext command must appear in outer paragraph mode.

Footnotes in a table
====================

Inside a table environment the \footnote command does not work.  For instance, if the code below appears on its own then the footnote simply disappears; there is a footnote mark in the table cell but nothing is set at the bottom of the page.

     \begin{center}
          \begin{tabular}{l|l}
          \textsc{Ship}  &\textsc{Book} \\ \hline
          \textit{HMS Sophie}     &Master and Commander  \\
          \textit{HMS Polychrest} &Post Captain  \\
          \textit{HMS Lively}     &Post Captain \\
          \textit{HMS Surprise}   &A number of books\footnote{Starting with HMS Surprise.}
          \end{tabular}
     \end{center}

The solution is to surround the tabular environment with a minipage environment, as here (see minipage).

     \begin{center}
       \begin{minipage}{.5\textwidth}
         .. tabular material ..
       \end{minipage}
     \end{center}

The same technique will work inside a floating table environment (see table).  To get the footnote at the bottom of the page use the tablefootnote package, as illustrated in this example.  If you put \usepackage{tablefootnote} in the preamble and use the code shown then the footnote appears at the bottom and is numbered in sequence with other footnotes.

     \begin{table}
       \centering
          \begin{tabular}{l|l}
          \textsc{Date}  &\textsc{Campaign} \\ \hline
          1862           &Fort Donelson \\
          1863           &Vicksburg     \\
          1865           &Army of Northern Virginia\footnote{Ending the war.}
          \end{tabular}
         \caption{Forces captured by US Grant}
     \end{table}

Footnotes in section headings
=============================

Putting a footnote in a section heading

     \section{Full sets\protect\footnote{This material is due to R~Jones.}}

causes the footnote to appear both at the bottom of the page where the section starts and at the bottom of the table of contents page.  To have it not appear on the table of contents use the package footmisc with the stable option.

     \usepackage[stable]{footmisc}
      ..
     \begin{document}
      ..
     \section{Full sets\footnote{This material is due to R~Jones.}}

Note that the \protect is gone; putting it in causes the footnote to reappear on the table of contents.

Footnotes of footnotes
======================

Particularly in the humanities, authors can have multiple classes of footnotes, including having footnotes of footnotes.  The package bigfoot extends LaTeX's default footnote mechanism in many ways, including allow these two, as in this example.

     \usepackage{bigfoot}
     \DeclareNewFootnote{Default}
     \DeclareNewFootnote{from}[alph]   % create class \footnotefrom{}
       ..
     \begin{document}
       ..
     The third theorem is a partial converse of the
     second.\footnotefrom{First noted in Wilson.\footnote{Second edition only.}}
      ..

Multiple references to footnotes
================================

You can refer to a single footnote more than once.  This example uses the package cleverref.

     \usepackage{cleveref}[2012/02/15]   % this version of package or later
     \crefformat{footnote}{#2\footnotemark[#1]#3}
       ..
     \begin{document}
       ..
     The theorem is from Evers.\footnote{\label{fn:TE}Tinker and Evers, 1994.}
     The corollary is from Chance.\footnote{Evers and Chance, 1990.}
     But the key lemma is from Tinker.\cref{fn:TE}
       ..

This solution will work with the package hyperref. See \footnotemark for a simpler solution in the common case of multiple authors with the same affiliation.

Footnote parameters
===================

\footnoterule
     Produces the rule separating the main text on a page from the page's footnotes.  Default dimensions: 0.4pt thick (or wide), and 0.4\columnwidth long in the standard document classes (except slides, where it does not appear).

\footnotesep
     The height of the strut placed at the beginning of the footnote.  By default, this is set to the normal strut for \footnotesize fonts (see Font sizes), therefore there is no extra space between footnotes.  This is 6.65pt for 10pt, 7.7pt for 11pt, and 8.4pt for 12pt.

Definitions
***********

LaTeX has support for making new commands of many different kinds.

\newcommand & \renewcommand
===========================

\newcommand and \renewcommand define and redefine a command, respectively.  Synopses:

       \newcommand{CMD}[NARGS][OPTARGDEFAULT]{DEFN}
       \newcommand*{CMD}[NARGS][OPTARGDEFAULT]{DEFN}
     \renewcommand{CMD}[NARGS][OPTARGDEFAULT]{DEFN}
     \renewcommand*{CMD}[NARGS][OPTARGDEFAULT]{DEFN}

The *-form of these two commands requires that the arguments not contain multiple paragraphs of text (not \long, in plain TeX terms).

cmd
     Required; the command name.  It must begin with \.  For \newcommand, it must not be already defined and must not begin with \end.  For \renewcommand, it must already be defined.

nargs
     Optional; an integer from 0 to 9, specifying the number of arguments that the command will take.  If this argument is not present, the default is for the command to have no arguments.  When redefining a command, the new version can have a different number of arguments than the old version.

optargdefault
     Optional; if this argument is present then the first argument of defined command \CMD is optional, with default value OPTARGDEFAULT (which may be the empty string).  If this argument is not present then \CMD does not take an optional argument.

     That is, if \CMD is used with square brackets following, as in \CMD[MYVAL], then within DEFN #1 expands MYVAL.  While if \CMD is called without square brackets following, then within DEFN the #1 expands to the default OPTARGDEFAULT.  In either case, any required arguments will be referred to starting with #2.

     Omitting [MYVAL] in the call is different from having the square brackets with no contents, as in [].  The former results in #1 expanding to OPTARGDEFAULT; the latter results in #1 expanding to the empty string.

defn
     The text to be substituted for every occurrence of cmd; a construct of the form #N in DEFN is replaced by the text of the Nth argument.

A command with no arguments that is followed in the source by a space will swallow that space.  The solution is to type {} after the command and before the space.

A simple example of defining a new command: \newcommand{\JH}{Jim Hef{}feron} causes the abbreviation \JH to be replaced by the longer text.

Redefining a command is basically the same: \renewcommand{\qedsymbol}{{\small QED}}.

Here's a command definition that uses arguments:

     \newcommand{\defreference}[1]{Definition~\ref{#1}}

Then, \defreference{def:basis} will expand to something like Definition~3.14.

An example with two arguments: \newcommand{\nbym}[2]{#1\!\times\!#2} is invoked as \nbym{2}{k}.

An example with optional arguments:

     \newcommand{\salutation}[1][Sir or Madam]{Dear #1:}

Then, \salutation gives Dear Sir or Madam: while \salutation[John] gives Dear John:.  And \salutation[] gives Dear :.

The braces around DEFN do not delimit the scope of the result of expanding DEFN.  So \newcommand{\shipname}[1]{\it #1} is wrong since in the sentence

     The \shipname{Monitor} met the \shipname{Virginia}.

the words met the will incorrectly be in italics.  An extra pair of braces \newcommand{\shipname}[1]{{\it #1}} fixes it.

\providecommand
===============

Defines a command, as long as no command of this name already exists. Synopses:

     \providecommand{CMD}[NARGS][OPTARGDEFAULT]{DEFN}
     \providecommand*{CMD}[NARGS][OPTARGDEFAULT]{DEFN}

If no command of this name already exists then this has the same effect as \newcommand (see \newcommand & \renewcommand).  If a command of this name already exists then this definition does nothing. This is particularly useful in a style file, or other file that may be loaded more than once.

\newcounter: Allocating a counter
=================================

Synopsis:

     \newcounter{COUNTERNAME}[SUPERCOUNTER]

The \newcounter command globally defines a new counter named COUNTERNAME.  The name consists of letters only and does not begin with a backslash (\).  The name must not already be used by another counter. The new counter is initialized to zero.

If the optional argument [SUPERCOUNTER] appears, then COUNTERNAME will be numbered within, or subsidiary to, the existing counter SUPERCOUNTER.  For example, ordinarily subsection is numbered within section.  Any time SUPERCOUNTER is incremented with \stepcounter (see \stepcounter) or \refstepcounter (see \refstepcounter) then COUNTERNAME is reset to zero.

See Counters, for more information about counters.

\newlength: Allocating a length
===============================

Allocate a new length register.  Synopsis:

     \newlength{\ARG}

This command takes one required argument, which must begin with a backslash (\).  It creates a new length register named \ARG, which is a place to hold (rubber) lengths such as 1in plus.2in minus.1in (what plain TeX calls a skip register).  The register gets an initial value of zero.  The control sequence \ARG must not already be defined.

See Lengths, for more about lengths.

\newsavebox: Allocating a box
=============================

Allocate a ``bin'' for holding a box.  Synopsis:

     \newsavebox{\CMD}

Defines \CMD to refer to a new bin for storing boxes. Such a box is for holding typeset material, to use multiple times (see Boxes) or to measure or manipulate.  The name \CMD must start with a backslash (\), and must not be already defined.

The allocation of a box is global.  This command is fragile (see \protect).

\newenvironment & \renewenvironment
===================================

These commands define or redefine an environment ENV, that is, \begin{ENV} ... \end{ENV}.  Synopses:

       \newenvironment{ENV}[NARGS][OPTARGDEFAULT]{BEGDEFN}{ENDDEFN}
       \newenvironment*{ENV}[NARGS][OPTARGDEFAULT]{BEGDEFN}{ENDDEFN}
     \renewenvironment{ENV}[NARGS][OPTARGDEFAULT]{BEGDEFN}{ENDDEFN}
     \renewenvironment*{ENV}[NARGS][OPTARGDEFAULT]{BEGDEFN}{ENDDEFN}

Unlike \newcommand and \renewcommand, the *-forms \newenvironment* and \renewcommand* have the same effect as the forms with no *.

env
     Required; the environment name.  It does not begin with backslash (\).  It must not begin with the string end.  For \newenvironment, the name ENV must not be the name of an already existing environment, and also the command \ENV must be undefined.  For \renewenvironment, ENV must be the name of an existing environment.

nargs
     Optional; an integer from 0 to 9 denoting the number of arguments of that the environment will take.  These arguments appear after the \begin, as in \begin{ENV}{ARG1}...{ARGN}.  If this argument is not present then the default is for the environment to have no arguments.  When redefining an environment, the new version can have a different number of arguments than the old version.

optargdefault
     Optional; if this argument is present then the first argument of the defined environment is optional, with default value OPTARGDEFAULT (which may be the empty string).  If this argument is not present then the environment does not take an optional argument.

     That is, when [OPTARGDEFAULT] is present in the environment definition, if \begin{ENV} is used with square brackets following, as in \begin{ENV}[MYVAL], then within the environment #1 expands MYVAL.  If \begin{ENV} is called without square brackets following, then within the environment the #1 expands to the default OPTARGDEFAULT.  In either case, any required arguments will be referred to starting with #2.

     Omitting [MYVAL] in the call is different from having the square brackets with no contents, as in [].  The former results in #1 expanding to OPTARGDEFAULT; the latter results in #1 expanding to the empty string.

begdefn
     Required; the text expanded at every occurrence of \begin{ENV}; a construct of the form #N in BEGDEF is replaced by the text of the Nth argument.

enddefn
     Required; the text expanded at every occurrence of \end{ENV}.  Note that it may not contain any argument parameters, so #N cannot be used here.

The environment ENV delimits the scope of the result of expanding BEGDEFN and ENDDEFN.  Thus, in the first example below, the effect of the \small is limited to the quote and does not extend to material following the environment.

This example gives an environment like LaTeX's quotation except that it will be set in smaller type.

     \newenvironment{smallquote}{%
       \small\begin{quotation}
     }{%
       \end{quotation}
     }

This shows the use of arguments; it gives a quotation environment that cites the author.

     \newenvironment{citequote}[1][Shakespeare]{%
       \begin{quotation}
       \noindent\textit{#1}:
     }{%
       \end{quotation}
     }

The author's name is optional, and defaults to Shakespeare. In the document, use the environment as here:

     \begin{citequote}[Lincoln]
       ..
     \end{citequote}

The final example shows how to save the value of an argument to use in ENDDEFN.

     \newsavebox{\quoteauthor}
     \newenvironment{citequote}[1][Shakespeare]{%
       \sbox\quoteauthor{#1}%
       \begin{quotation}
     }{%
       \hspace{1em plus 1fill}---\usebox{\quoteauthor}
       \end{quotation}
     }

\newtheorem
===========

Define a new theorem-like environment.  Synopses:

     \newtheorem{NAME}{TITLE}[NUMBERED_WITHIN]
     \newtheorem{NAME}[NUMBERED_LIKE]{TITLE}

Both create a theorem-like environment NAME.  Using the first form,

     \newtheorem{NAME}{TITLE}[NUMBERED_WITHIN]

with the optional argument after the second required argument, creates an environment whose counter is subordinate to the existing counter NUMBERED_WITHIN: it will be reset when NUMBERED_WITHIN is reset).

Using the second form,

     \newtheorem{NAME}[NUMBERED_LIKE]{TITLE}

with the optional argument between the two required arguments, will create an environment whose counter will share the previously defined counter NUMBERED_LIKE.

You can specify one of NUMBERED_WITHIN and NUMBERED_LIKE, or neither, but not both.

This command creates a counter named NAME.  In addition, unless the optional argument NUMBERED_LIKE is used, the current \ref value will be that of \theNUMBERED_WITHIN (see \ref).

This declaration is global.  It is fragile (see \protect).

Arguments:

name
     The name of the environment.  It must not begin with a backslash (\).  It must not be the name of an existing environment; indeed, the command name \NAME must not already be defined as anything.

title
     The text printed at the beginning of the environment, before the number. For example, Theorem.

numbered_within
     Optional; the name of an already defined counter, usually a sectional unit such as chapter or section.  When the NUMBERED_WITHIN counter is reset then the NAME environment's counter will also be reset.

     If this optional argument is not used then the command \theNAME is set to \arabic{NAME}.

numbered_like
     Optional; the name of an already defined theorem-like environment. The new environment will be numbered in sequence with NUMBERED_LIKE.

Without any optional arguments the environments are numbered sequentially.  This example has a declaration in the preamble that results in Definition 1 and Definition 2 in the output.

     \newtheorem{defn}{Definition}
     \begin{document}
     \section{...}
     \begin{defn}
       First def
     \end{defn}

     \section{...}
     \begin{defn}
       Second def
     \end{defn}

Because this example specifies the optional argument NUMBERED_WITHIN to \newtheorem as section, the example, with the same document body, gives Definition 1.1 and Definition 2.1.

     \newtheorem{defn}{Definition}[section]
     \begin{document}
     \section{...}
     \begin{defn}
       First def
     \end{defn}

     \section{...}
     \begin{defn}
       Second def
     \end{defn}

In this example there are two declarations in the preamble, the second of which calls for the new thm environment to use the same counter as defn.  It gives Definition 1.1, followed by Theorem 2.1 and Definition 2.2.

     \newtheorem{defn}{Definition}[section]
     \newtheorem{thm}[defn]{Theorem}
     \begin{document}
     \section{...}
     \begin{defn}
       First def
     \end{defn}

     \section{...}
     \begin{thm}
       First thm
     \end{thm}

     \begin{defn}
       Second def
     \end{defn}

\newfont: Define a new font (obsolete)
======================================

\newfont, now obsolete, defines a command that will switch fonts. Synopsis:

     \newfont{\CMD}{FONT DESCRIPTION}

This defines a control sequence \CMD that will change the current font.  LaTeX will look on your system for a file named FONTNAME.tfm.  The control sequence must must not already be defined.  It must begin with a backslash (\).

This command is obsolete.  It is a low-level command for setting up an individual font.  Today fonts are almost always defined in families (which allows you to, for example, associate a boldface with a roman) through the so-called ``New Font Selection Scheme'', either by using .fd files or through the use of an engine that can access system fonts such as XeLaTeX (see TeX engines).

But since it is part of LaTeX, here is an explanation: the FONT DESCRIPTION consists of a FONTNAME and an optional at clause; this can have the form either at DIMEN or scaled FACTOR, where a FACTOR of 1000 means no scaling.  For LaTeX's purposes, all this does is scale all the character and other font dimensions relative to the font's design size, which is a value defined in the .tfm file.

This example defines two equivalent fonts and typesets a few characters in each:

     \newfont{\testfontat}{cmb10 at 11pt}
     \newfont{\testfontscaled}{cmb10 scaled 11pt}
     \testfontat abc
     \testfontscaled abc

\protect
========

All LaTeX commands are either fragile or robust. Footnotes, line breaks, any command that has an optional argument, and many more, are fragile.  A fragile command can break when it is used in the argument to certain commands.  To prevent such commands from breaking they must be preceded by the command \protect.

For example, when LaTeX runs the \section{SECTION NAME} command it writes the SECTION NAME text to the .aux auxiliary file, moving it there for use elsewhere in the document such as in the table of contents.  Any argument that is internally expanded by LaTeX without typesetting it directly is referred to as a moving argument.  A command is fragile if it can expand during this process into invalid TeX code.  Some examples of moving arguments are those that appear in the \caption{..} command (see figure), in the \thanks{..} command (see \maketitle), and in @-expressions in the tabular and array environments (see tabular).

If you get strange errors from commands used in moving arguments, try preceding it with \protect.  Every fragile commands must be protected with their own \protect.

Although usually a \protect command doesn't hurt, length commands are robust and should not be preceded by a \protect command. Nor can a \protect command be used in the argument to \addtocounter or \setcounter command.

In this example the caption command gives a mysterious error about an extra curly brace.  Fix the problem by preceding each \raisebox command with \protect.

     \begin{figure}
       ..
       \caption{Company headquarters of A\raisebox{1pt}{B}\raisebox{-1pt}{C}}
     \end{figure}

In the next example the \tableofcontents command gives an error because the \(..\) in the section title expands to illegal TeX in the .toc file.  You can solve this by changing \(..\) to \protect\(..\protect\).

     \begin{document}
     \tableofcontents
      ..
     \section{Einstein's \( e=mc^2 \)}
      ..

Counters
********

Everything LaTeX numbers for you has a counter associated with it. The name of the counter is often the same as the name of the environment or command associated with the number, except with no backslash (\).  Thus the \chapter command starts a chapter and the chapter counter keeps track of the chapter number.  Below is a list of the counters used in LaTeX's standard document classes to control numbering.

     part            paragraph       figure          enumi
     chapter         subparagraph    table           enumii
     section         page            footnote        enumiii
     subsection      equation        mpfootnote      enumiv
     subsubsection

The mpfootnote counter is used by the \footnote command inside of a minipage (see minipage).

The enumi through enumiv counters are used in the enumerate environment, for up to four nested levels (see enumerate).

New counters are created with \newcounter.  See \newcounter.

\alph \Alph \arabic \roman \Roman \fnsymbol: Printing counters
==============================================================

All of these commands take a single counter as an argument, for instance, \alph{enumi}.  Note that the counter name does not start with a backslash.

\alph
     prints COUNTER using lowercase letters: `a', `b', ...

\Alph
     uses uppercase letters: `A', `B', ...

\arabic
     uses Arabic numbers: `1', `2', ...

\roman
     uses lowercase roman numerals: `i', `ii', ...

\Roman
     uses uppercase roman numerals: `I', `II', ...

\fnsymbol
     prints the value of COUNTER in a specific sequence of nine symbols (conventionally used for labeling footnotes).  The value of COUNTER must be between 1 and 9, inclusive.

     Here are the symbols (as Unicode code points in ASCII output):

          asterisk(*) dagger(‡) ddagger(‡)
          section-sign(§) paragraph-sign(¶) parallel(∥)
          double-asterisk(**) double-dagger(††) double-ddagger(‡‡)

\usecounter{COUNTER}
====================

Synopsis:

     \usecounter{COUNTER}

In the list environment, when used in the second argument, this command sets up COUNTER to number the list items.  It initializes COUNTER to zero, and arranges that when \item is called without its optional argument then COUNTER is incremented by \refstepcounter, making its value be the current ref value.  This command is fragile (see \protect).

Put in the preamble, this makes a new list environment enumerated with TESTCOUNTER:

     \newcounter{testcounter}
     \newenvironment{test}{%
       \begin{list}{}{%
         \usecounter{testcounter}
       }
     }{%
       \end{list}
     }

\value{COUNTER}
===============

Synopsis:

     \value{COUNTER}

This command expands to the value of COUNTER.  It is often used in \setcounter or \addtocounter, but \value can be used anywhere that LaTeX expects a number.  It must not be preceded by \protect (see \protect).

The \value command is not used for typesetting the value of the counter.  See \alph \Alph \arabic \roman \Roman \fnsymbol.

This example outputs Test counter is 6. Other counter is 5..

     \newcounter{test} \setcounter{test}{5}
     \newcounter{other} \setcounter{other}{\value{test}}
     \addtocounter{test}{1}

     Test counter is \arabic{test}.
     Other counter is \arabic{other}.

This example inserts \hspace{4\parindent}.

     \setcounter{myctr}{3} \addtocounter{myctr}{1}
     \hspace{\value{myctr}\parindent}

\setcounter{COUNTER}{VALUE}
===========================

Synopsis:

     \setcounter{COUNTER}{VALUE}

The \setcounter command globally sets the value of COUNTER to the VALUE argument.  Note that the counter name does not start with a backslash.

\addtocounter{COUNTER}{VALUE}
=============================

The \addtocounter command globally increments COUNTER by the amount specified by the VALUE argument, which may be negative.

\refstepcounter{COUNTER}
========================

The \refstepcounter command works in the same way as \stepcounter (see \stepcounter): it globally increments the value of COUNTER by one and resets the value of any counter numbered within it.  (For the definition of ``counters numbered within'', see \newcounter.)

In addition, this command also defines the current \ref value to be the result of \thecounter.

While the counter value is set globally, the \ref value is set locally, i.e., inside the current group.

\stepcounter{COUNTER}
=====================

The \stepcounter command globally adds one to COUNTER and resets all counters numbered within it.  (For the definition of ``counters numbered within'', see \newcounter.)

\day \month \year: Predefined counters
======================================

LaTeX defines counters for the day of the month (\day, 1--31), month of the year (\month, 1--12), and year (\year, Common Era).  When TeX starts up, they are set to the current values on the system where TeX is running.  They are not updated as the job progresses.

The related command \today produces a string representing the current day (see \today).

Lengths
*******

A length is a measure of distance.  Many LaTeX commands take a length as an argument.

Lengths come in two types.  A rigid length (what Plain TeX calls a dimen) such as 10pt cannot contain a plus or minus component.  A rubber length (what Plain TeX calls a skip) can contain those, as with 1cm plus0.05cm minus0.01cm.  These give the ability to stretch or shrink; the length in the prior sentence could appear in the output as long as 1.05 cm or as short as 0.99 cm, depending on what TeX's typesetting algorithm finds optimum.

The plus or minus component of a rubber length can contain a fill component, as in 1in plus2fill.  This gives the length infinite stretchability or shrinkability, so that the length in the prior sentence can be set by TeX to any distance greater than or equal to 1 inch.  TeX actually provides three infinite glue components fil, fill, and filll, such that the later ones overcome the earlier ones, but only the middle value is ordinarily used.  See \hfill, see \vfill.

Multiplying an entire rubber length by a number turns it into a rigid length, so that after \setlength{\ylength}{1in plus 0.2in} and \setlength{\zlength}{3\ylength} then the value of \zlength is 3in.

Units of length
===============

TeX and LaTeX know about these units both inside and outside of math mode.

pt
     Point 1/72.27 inch.  The conversion to metric units, to two decimal places, is 1point = 2.85mm = 28.45cm.

pc
     Pica, 12 pt

in
     Inch,  72.27 pt

bp
     Big point, 1/72 inch.  This length is the definition of a point in PostScript and many desktop publishing systems.

cm
     Centimeter

mm
     Millimeter

dd
     Didot point, 1.07 pt

cc
     Cicero, 12 dd

sp
     Scaled point, 1/65536 pt

Two other lengths that are often used are values set by the designer of the font.  The x-height of the current font ex, traditionally the height of the lower case letter x, is often used for vertical lengths. Similarly em, traditionally the width of the capital letter M, is often used for horizontal lengths (there is also \enspace, which is 0.5em).  Use of these can help make a definition work better across font changes.  For example, a definition of the vertical space between list items given as \setlength{\itemsep}{1ex plus 0.05ex minus 0.01ex} is more likely to still be reasonable if the font is changed than a definition given in points.

In math mode, many definitions are expressed in terms of the math unit mu given by 1 em = 18 mu, where the em is taken from the current math symbols family.  See Spacing in math mode.

\setlength{\LEN}{VALUE}
=======================

The \setlength sets the value of \LEN to the VALUE argument, which can be expressed in any units that LaTeX understands, i.e., inches (in), millimeters (mm), points (pt), big points (bp, etc.

\addtolength{\LEN}{AMOUNT}
==========================

The \addtolength command increments a ``length command'' \LEN by the amount specified in the AMOUNT argument, which may be negative.

\settodepth
===========

\settodepth{\gnat}{text}

The \settodepth command sets the value of a length command equal to the depth of the text argument.

\settoheight
============

\settoheight{\gnat}{text}

The \settoheight command sets the value of a length command equal to the height of the text argument.

\settowidth{\LEN}{TEXT}
=======================

The \settowidth command sets the value of the command \LEN to the width of the TEXT argument.

Predefined lengths
==================

\width

\height

\depth

\totalheight

These length parameters can be used in the arguments of the box-making commands (see Boxes).  They specify the natural width, etc., of the text in the box. \totalheight equals \height + \depth. To make a box with the text stretched to double the natural size, e.g., say

\makebox[2\width]{Get a stretcher}

Making paragraphs
*****************

A paragraph is ended by one or more completely blank lines---lines not containing even a %.  A blank line should not appear where a new paragraph cannot be started, such as in math mode or in the argument of a sectioning command.

\indent
=======

\indent produces a horizontal space whose width equals to the \parindent length, the normal paragraph indentation.  It is used to add paragraph indentation where it would otherwise be suppressed.

The default value for \parindent is 1em in two-column mode, otherwise 15pt for 10pt documents, 17pt for 11pt, and 1.5em for 12pt.

\noindent
=========

When used at the beginning of the paragraph, this command suppresses any paragraph indentation, as in this example.

     .. end of the prior paragraph.

     \noindent This paragraph is not indented.

It has no effect when used in the middle of a paragraph.

To eliminate paragraph indentation in an entire document, put \setlength{\parindent}{0pt} in the preamble.

\parskip
========

\parskip is a rubber length defining extra vertical space added before each paragraph.  The default is 0pt plus1pt.

Marginal notes
==============

Synopsis:

     \marginpar[LEFT]{RIGHT}

The \marginpar command creates a note in the margin.  The first line of the note will have the same baseline as the line in the text where the \marginpar occurs.

When you only specify the mandatory argument RIGHT, the text will be placed

  * in the right margin for one-sided layout (option oneside, see Document class options);

  * in the outside margin for two-sided layout (option twoside, see Document class options);

  * in the nearest margin for two-column layout (option twocolumn, see Document class options).

The command \reversemarginpar places subsequent marginal notes in the opposite (inside) margin.  \normalmarginpar places them in the default position.

When you specify both arguments, LEFT is used for the left margin, and RIGHT is used for the right margin.

The first word will normally not be hyphenated; you can enable hyphenation there by beginning the node with \hspace{0pt}.

These parameters affect the formatting of the note:

\marginparpush
     Minimum vertical space between notes; default 7pt for 12pt documents, 5pt else.

\marginparsep
     Horizontal space between the main text and the note; default 11pt for 10pt documents, 10pt else.

\marginparwidth
     Width of the note itself; default for a one-sided 10pt document is 90pt, 83pt for 11pt, and 68pt for 12pt; 17pt more in each case for a two-sided document. In two column mode, the default is 48pt.

The standard LaTeX routine for marginal notes does not prevent notes from falling off the bottom of the page.

Math formulas
*************

There are three environments that put LaTeX in math mode:

math
     For formulas that appear right in the text.

displaymath
     For formulas that appear on their own line.

equation
     The same as the displaymath environment except that it adds an equation number in the right margin.

The math environment can be used in both paragraph and LR mode, but the displaymath and equation environments can be used only in paragraph mode.  The math and displaymath environments are used so often that they have the following short forms:

     \(...\)   instead of   \begin{math}...\end{math}
     \[...\]   instead of   \begin{displaymath}...\end{displaymath}

In fact, the math environment is so common that it has an even shorter form:

     $ ... $   instead of   \(...\)

The \boldmath command changes math letters and symbols to be in a bold font.  It is used outside of math mode.  Conversely, the \unboldmath command changes math glyphs to be in a normal font; it too is used outside of math mode.

The \displaystyle declaration forces the size and style of the formula to be that of displaymath, e.g., with limits above and below summations.  For example:

     $\displaystyle \sum_{n=0}^\infty x_n $

Subscripts & superscripts
=========================

In math mode, use the caret character ^ to make the EXP appear as a superscript, ie. type ^{EXP}. Similarly, in math mode, underscore _{EXP} makes a subscript out of EXP.

In this example the 0 and 1 appear as subscripts while the 2 is a superscript.

     \( (x_0+x_1)^2 \)

To have more than one character in EXP use curly braces as in e^{-2x}.

LaTeX handles superscripts on superscripts, and all of that stuff, in the natural way, so expressions such as e^{x^2} and x_{a_0} will look right.  It also does the right thing when something has both a subscript and a superscript.  In this example the 0 appears at the bottom of the integral sign while the 10 appears at the top.

     \int_0^{10} x^2 \,dx

You can put a superscript or subscript before a symbol with a construct such as {}_t K^2 in math mode (the initial {} prevents the prefixed subscript from being attached to any prior symbols in the expression).

Outside of math mode, a construct like A test$_\textnormal{subscript}$ will produce a subscript typeset in text mode, not math mode.  Note that there are packages specialized for writing Chemical formulas such as mhchem.

Math symbols
============

LaTeX provides almost any mathematical symbol you're likely to need. For example, if you include $\pi$ in your source, you will get the pi symbol.

Below is a list of commonly-available symbols.  It is by no means an exhaustive list.  Each symbol here is described with a short phrase, and its symbol class (which determines the spacing around it) is given in parenthesis.  The commands for these symbols can be used only in math mode.

\|
     Parallel (relation). Synonym: \parallel.

\aleph
     Aleph, transfinite cardinal (ordinary).

\alpha
     Lower case Greek letter alpha (ordinary).

\amalg
     Disjoint union (binary)

\angle
     Geometric angle (ordinary). Similar: less-than sign < and angle bracket \langle.

\approx
     Almost equal to (relation).

\ast
     Asterisk operator, convolution, six-pointed (binary). Synonym: *, which is often a superscript or subscript, as in the Kleene star. Similar: \star, which is five-pointed, and is sometimes used as a general binary operation, and sometimes reserved for cross-correlation.

\asymp
     Asymptomatically equivalent (relation).

\backslash
     \ Backslash (ordinary).  Similar: set minus \setminus, and \textbackslash for backslash outside of math mode.

\beta
     Lower case Greek letter beta (ordinary).

\bigcap
     Variable-sized, or n-ary, intersection (operator). Similar: binary intersection \cap.

\bigcirc
     Circle, larger (binary).  Similar: function composition \circ.

\bigcup
     Variable-sized, or n-ary, union (operator). Similar: binary union \cup.

\bigodot
     Variable-sized, or n-ary, circled dot operator (operator).

\bigoplus
     Variable-sized, or n-ary, circled plus operator (operator).

\bigotimes
     Variable-sized, or n-ary, circled times operator (operator).

\bigtriangledown
     Variable-sized, or n-ary, open triangle pointing down (operator).

\bigtriangleup
     Variable-sized, or n-ary, open triangle pointing up (operator).

\bigsqcup
     Variable-sized, or n-ary, square union (operator).

\biguplus
     Variable-sized, or n-ary, union operator with a plus (operator).  (Note that the name has only one p.)

\bigvee
     Variable-sized, or n-ary, logical-and (operator).

\bigwedge
     Variable-sized, or n-ary, logical-or (operator).

\bot
     Up tack, bottom, least element of a poset, or a contradiction (ordinary).  See also \top.

\bowtie
     Natural join of two relations (relation).

\Box
     Modal operator for necessity; square open box (ordinary).  This is not available in Plain TeX.  In LaTeX you need to load the amssymb package.

\bullet
     Bullet (binary).  Similar: multiplication dot \cdot.

\cap
     Intersection of two sets (binary).  Similar: variable-sized operator \bigcap.

\cdot
     Multiplication (binary).  Similar: Bullet dot \bullet.

\chi
     Lower case Greek chi (ordinary).

\circ
     Function composition, ring operator (binary).  Similar: variable-sized operator \bigcirc.

\clubsuit
     Club card suit (ordinary).

\complement
     Set complement, used as a superscript as in $S^\complement$ (ordinary).  This is not available in Plain TeX.  In LaTeX you should load the amssymb package. Also used: $S^{\mathsf{c}}$ or $\bar{S}$.

\cong
     Congruent (relation).

\coprod
     Coproduct (operator).

\cup
     Union of two sets (binary).  Similar: variable-sized operator \bigcup.

\dagger
     Dagger relation (binary).

\dashv
     Dash with vertical, reversed turnstile (relation).  Similar: turnstile \vdash.

\ddagger
     Double dagger relation (binary).

\Delta
     Greek upper case delta, used for increment (ordinary).

\delta
     Greek lower case delta (ordinary).

\Diamond
     Large diamond operator (ordinary).  This is not available in Plain TeX.  In LaTeX you must load the amssymb package.

\diamond
     Diamond operator, or diamond bullet (binary).  Similar: large diamond \Diamond, circle bullet \bullet.

\diamondsuit
     Diamond card suit (ordinary).

\div
     Division sign (binary).

\doteq
     Approaches the limit (relation).  Similar: geometrically equal to \Doteq.

\downarrow
     Down arrow, converges (relation).  Similar: double line down arrow \Downarrow.

\Downarrow
     Double line down arrow (relation).  Similar: single line down arrow \downarrow.

\ell
     Lower-case cursive letter l (ordinary).

\emptyset
     Empty set symbol (ordinary).  Similar: reversed empty set \varnothing.

\epsilon
     Lower case Greek-text letter (ordinary).  More widely used in mathematics is the curly epsilon \varepsilon. Related: the set membership relation \in.

\equiv
     Equivalence (relation).

\eta
     Lower case Greek letter (ordinary).

\exists
     Existential quantifier (ordinary).

\flat
     Musical flat (ordinary).

\forall
     Universal quantifier (ordinary).

\frown
     Downward curving arc (ordinary).

\Gamma
     Upper case Greek letter (ordinary).

\gamma
     Lower case Greek letter (ordinary).

\ge
     Greater than or equal to (relation).  This is a synonym for \geq.

\geq
     Greater than or equal to (relation).  This is a synonym for \ge.

\gets
     Is assigned the value (relation). Synonym: \leftarrow.

\gg
     Much greater than (relation).  Similar: much less than \ll.

\hbar
     Planck constant over two pi (ordinary).

\heartsuit
     Heart card suit (ordinary).

\hookleftarrow
     Hooked left arrow (relation).

\hookrightarrow
     Hooked right arrow (relation).

\iff
     If and only if (relation).  It is \Longleftrightarrow with a \thickmuskip on either side.

\Im
     Imaginary part (ordinary).  See: real part \Re.

\in
     Set element (relation).  See also: lower case Greek letter epsilon \epsilon and rounded small epsilon \varepsilon.

\infty
     Infinity (ordinary).

\int
     Integral (operator).

\iota
     Lower case Greek letter (ordinary).

\Join
     Condensed bowtie symbol (relation).  Not available in Plain TeX.

\kappa
     Lower case Greek letter (ordinary).

\Lambda
     Upper case Greek letter (ordinary).

\lambda
     Lower case Greek letter (ordinary).

\land
     Logical and (binary).  This is a synonym for \wedge. See also logical or \lor.

\langle
     Left angle, or sequence, bracket (opening).  Similar: less-than <. Matches \rangle.

\lbrace
     Left curly brace (opening). Synonym: \{. Matches \rbrace.

\lbrack
     Left square bracket (opening). Synonym: [. Matches \rbrack.

\lceil
     Left ceiling bracket, like a square bracket but with the bottom shaved off (opening). Matches \rceil.

\le
     Less than or equal to (relation).  This is a synonym for \leq.

\leadsto
     Squiggly right arrow (relation).  This is not available in Plain TeX.  In LaTeX you should load the amssymb package. To get this symbol outside of math mode you can put \newcommand*{\Leadsto}{\ensuremath{\leadsto}} in the preamble and then use \Leadsto instead.

\Leftarrow
     Is implied by, double-line left arrow (relation).  Similar: single-line left arrow \leftarrow.

\leftarrow
     Single-line left arrow (relation). Synonym: \gets. Similar: double-line left arrow \Leftarrow.

\leftharpoondown
     Single-line left harpoon, barb under bar (relation).

\leftharpoonup
     Single-line left harpoon, barb over bar (relation).

\Leftrightarrow
     Bi-implication; double-line double-headed arrow (relation). Similar: single-line double headed arrow \leftrightarrow.

\leftrightarrow
     Single-line double-headed arrow (relation).  Similar: double-line double headed arrow \Leftrightarrow.

\leq
     Less than or equal to (relation).  This is a synonym for \le.

\lfloor
     Left floor bracket (opening).

\lhd
     Arrowhead, that is, triangle, pointing left (binary).  This is not available in Plain TeX.  In LaTeX you should load the amssymb package. For the normal subgroup symbol you should load amssymb and use \vartriangleleft (which is a relation and so gives better spacing).

\ll
     Much less than (relation).  Similar: much greater than \gg.

\lnot
     Logical negation (ordinary). Synonym: \neg.

\longleftarrow
     Long single-line left arrow (relation).  Similar: long double-line left arrow \Longleftarrow.

\longleftrightarrow
     Long single-line double-headed arrow (relation).  Similar: long double-line double-headed arrow \Longleftrightarrow.

\longmapsto
     Long single-line left arrow starting with vertical bar (relation).  Similar: shorter version \mapsto.

\longrightarrow
     Long single-line right arrow (relation).  Similar: long double-line right arrow \Longrightarrow.

\lor
     Logical or (binary).  Synonym: wedge \wedge.

\mapsto
     Single-line left arrow starting with vertical bar (relation). Similar: longer version \longmapsto.

\mho
     Conductance, half-circle rotated capital omega (ordinary). This is not available in Plain TeX.  In LaTeX you should load the amssymb package.

\mid
     Single-line vertical bar (relation).  A typical use of \mid is for a set \{\, x \mid x\geq 5 \,\}.

     Similar: \vert and | produce the same single-line vertical bar symbol but without any spacing (they fall in class ordinary) and you should not use them as relations but instead only as ordinals, i.e., footnote symbols.  For absolute value, see the entry for \vert and for norm see the entry for \Vert.

\models
     Entails, or satisfies; double turnstile, short double dash (relation).  Similar: long double dash \vDash.

\mp
     Minus or plus (relation).

\mu
     Lower case Greek letter (ordinary).

\nabla
     Hamilton's del, or differential, operator (ordinary).

\natural
     Musical natural notation (ordinary).

\ne
     Not equal (relation). Synonym: \neq.

\nearrow
     North-east arrow (relation).

\neg
     Logical negation (ordinary). Synonym: \lnot. Sometimes instead used for negation: \sim.

\neq
     Not equal (relation). Synonym: \ne.

\ni
     Reflected membership epsilon; has the member (relation). Synonym: \owns. Similar: is a member of \in.

\not
     Long solidus, or slash, used to overstrike a following operator (relation).

     Many negated operators that don't require \not are available, particularly with the amssymb package. For example, \notin is probably typographically preferable to \not\in.

\notin
     Not an element of (relation).  Similar: not subset of \nsubseteq.

\nu
     Lower case Greek letter (ordinary).

\nwarrow
     North-west arrow (relation).

\odot
     Dot inside a circle (binary).  Similar: variable-sized operator \bigodot.

\oint
     Contour integral, integral with circle in the middle (operator).

\Omega
     Upper case Greek letter (ordinary).

\omega
     Lower case Greek letter (ordinary).

\ominus
     Minus sign, or dash, inside a circle (binary).

\oplus
     Plus sign inside a circle (binary).  Similar: variable-sized operator \bigoplus.

\oslash
     Solidus, or slash, inside a circle (binary).

\otimes
     Times sign, or cross, inside a circle (binary).  Similar: variable-sized operator \bigotimes.

\owns
     Reflected membership epsilon; has the member (relation). Synonym: \ni. Similar: is a member of \in.

\parallel
     Parallel (relation). Synonym: \|.

\partial
     Partial differential (ordinary).

\perp
     Perpendicular (relation).  Similar: \bot uses the same glyph but the spacing is different because it is in the class ordinary.

\phi
     Lower case Greek letter (ordinary).  The variant form is \varphi.

\Pi
     Upper case Greek letter (ordinary).

\pi
     Lower case Greek letter (ordinary).  The variant form is \varpi.

\pm
     Plus or minus (binary).

\prec
     Preceeds (relation). Similar: less than <.

\preceq
     Preceeds or equals (relation). Similar: less than or equals \leq.

\prime
     Prime, or minute in a time expression (ordinary).  Typically used as a superscript $A^\prime$.  Note that $f^\prime$ and $f'$ produce the same result.  An advantage of the second is that $f'''$ produces the the desired symbol, that is, the same result as $f^{\prime\prime\prime}$, but uses somewhat less typing. Note that you can only use \prime in math mode but you can type right single quote ' in text mode also, although it resuts in a different look than in math mode.

\prod
     Product (operator).

\propto
     Is proportional to (relation)

\Psi
     Upper case Greek letter (ordinary).

\psi
     Lower case Greek letter (ordinary).

\rangle
     Right angle, or sequence, bracket (closing). Similar: greater than >.  Matches:\langle.

\rbrace
     Right curly brace (closing). Synonym: \}. Matches \lbrace.

\rbrack
     Right square bracket (closing). Synonym: ]. Matches \lbrack.

\rceil
     Right ceiling bracket (closing). Matches \lceil.

\Re
     Real part, real numbers, cursive capital R (ordinary). Related: double-line, or blackboard bold, R \mathbb{R}; to access this, load the amsfonts package.

\restriction
     Restriction of a function (relation). Synonym: \upharpoonright.  Not available in Plain TeX.  In LaTeX you should load the amssymb package.

\rfloor
     Right floor bracket, a right square bracket with the top cut off (closing). Matches \lfloor.

\rhd
     Arrowhead, that is, triangle, pointing right (binary).  This is not available in Plain TeX.  In LaTeX you should load the amssymb package. For the normal subgroup symbol you should instead load amssymb and use \vartriangleright (which is a relation and so gives better spacing).

\rho
     Lower case Greek letter (ordinary).  The variant form is \varrho.

\Rightarrow
     Implies, right-pointing double line arrow (relation). Similar: right single-line arrow \rightarrow.

\rightarrow
     Right-pointing single line arrow (relation). Synonym: \to. Similar: right double line arrow \Rightarrow.

\rightharpoondown
     Right-pointing harpoon with barb below the line (relation).

\rightharpoonup
     Right-pointing harpoon with barb above the line (relation).

\rightleftharpoons
     Right harpoon up above left harpoon down (relation).

\searrow
     Arrow pointing southeast (relation).

\setminus
     Set difference, reverse solidus or slash, like \ (binary). Similar: backslash \backslash and also \textbackslash outside of math mode.

\sharp
     Musical sharp (ordinary).

\Sigma
     Upper case Greek letter (ordinary).

\sigma
     Lower case Greek letter (ordinary). The variant form is \varsigma.

\sim
     Similar, in a relation (relation).

\simeq
     Similar or equal to, in a relation (relation).

\smallint
     Integral sign that does not change to a larger size in a display (operator).

\smile
     Upward curving arc (ordinary).

\spadesuit
     Spade card suit (ordinary).

\sqcap
     Square intersection symbol (binary). Similar: intersection cap.

\sqcup
     Square union symbol (binary). Similar: union cup. Related: variable-sized operator \bigsqcup.

\sqsubset
     Square subset symbol (relation). Similar: subset \subset. This is not available in Plain TeX.  In LaTeX you should load the amssymb package.

\sqsubseteq
     Square subset or equal symbol (binary). Similar: subset or equal to \subseteq.

\sqsupset
     Square superset symbol (relation). Similar: superset \supset. This is not available in Plain TeX.  In LaTeX you should load the amssymb package.

\sqsupseteq
     Square superset or equal symbol (binary). Similar: superset or equal \supseteq.

\star
     Five-pointed star, sometimes used as a general binary operation but sometimes reserved for cross-correlation (binary). Similar: the synonyms asterisk * and \ast, which are six-pointed, and more often appear as a superscript or subscript, as with the Kleene star.

\subset
     Subset (occasionally, is implied by) (relation).

\subseteq
     Subset or equal to (relation).

\succ
     Comes after, succeeds (relation). Similar: is less than >.

\succeq
     Succeeds or is equal to (relation). Similar: less than or equal to \leq.

\sum
     Summation (operator). Similar: Greek capital sigma \Sigma.

\supset
     Superset (relation).

\supseteq
     Superset or equal to (relation).

\surd
     Radical symbol (ordinary).  The LaTeX command \sqrt{..} typesets the square root of the argument, with a bar that extends to cover the argument.

\swarrow
     Southwest-pointing  arrow (relation).

\tau
     Lower case Greek letter (ordinary).

\theta
     Lower case Greek letter (ordinary). The variant form is \vartheta.

\times
     Primary school multiplication sign (binary). See also \cdot.

\to
     Right-pointing single line arrow (relation). Synonym: \rightarrow.

\top
     Top, greatest element of a poset (ordinary). See also \bot.

\triangle
     Triangle (ordinary).

\triangleleft
     Not-filled triangle pointing left (binary). Similar: \lhd. For the normal subgroup symbol you should load amssymb and use \vartriangleleft (which is a relation and so gives better spacing).

\triangleright
     Not-filled triangle pointing right (binary). For the normal subgroup symbol you should instead load amssymb and use \vartriangleright (which is a relation and so gives better spacing).

\unlhd
     Left-pointing not-filled arrowhead, that is, triangle, with a line under (binary). This is not available in Plain TeX.  In LaTeX you should load the amssymb package.  For the normal subgroup symbol load amssymb and use \vartrianglelefteq (which is a relation and so gives better spacing).

\unrhd
     Right-pointing not-filled arrowhead, that is, triangle, with a line under (binary). This is not available in Plain TeX.  In LaTeX you should load the amssymb package.  For the normal subgroup symbol load amssymb and use \vartrianglerighteq (which is a relation and so gives better spacing).

\Uparrow
     Double-line upward-pointing arrow (relation). Similar: single-line up-pointing arrow \uparrow.

\uparrow
     Single-line upward-pointing arrow, diverges (relation). Similar: double-line up-pointing arrow \Uparrow.

\Updownarrow
     Double-line upward-and-downward-pointing arrow (relation). Similar: single-line upward-and-downward-pointing arrow \updownarrow.

\updownarrow
     Single-line upward-and-downward-pointing arrow (relation). Similar: double-line upward-and-downward-pointing arrow \Updownarrow.

\upharpoonright
     Up harpoon, with barb on right side (relation). Synonym: \restriction.  Not available in Plain TeX.  In LaTeX you should load the amssymb package.

\uplus
     Multiset union, a union symbol with a plus symbol in the middle (binary). Similar: union \cup. Related: variable-sized operator \biguplus.

\Upsilon
     Upper case Greek letter (ordinary).

\upsilon
     Lower case Greek letter (ordinary).

\varepsilon
     Rounded small epsilon (ordinary).  This is more widely used in mathematics than the non-variant lower case Greek-text letter form \epsilon. Related: set membership \in.

\varphi
     Variant on the lower case Greek letter (ordinary).  The non-variant form is \phi.

\varpi
     Variant on the lower case Greek letter (ordinary).  The non-variant form is \pi.

\varrho
     Variant on the lower case Greek letter (ordinary).  The non-variant form is \rho.

\varsigma
     Variant on the lower case Greek letter (ordinary).  The non-variant form is \sigma.

\vartheta
     Variant on the lower case Greek letter (ordinary).  The non-variant form is \theta.

\vdash
     Provable; turnstile, vertical and a dash (relation). Similar: turnstile rotated a half-circle \dashv.

\vee
     Logical or; a downwards v shape (binary). Related: logical and \wedge. Similar: variable-sized operator \bigvee.

\Vert
     Vertical double bar (ordinary). Similar: vertical single bar \vert.

     For a norm you can use the mathtools package and add \DeclarePairedDelimiter\norm{\lVert}{\rVert} to your preamble. This gives you three command variants for double-line vertical bars that are correctly horizontally spaced: if in the document body you write the starred version $\norm*{M^\perp}$ then the height of the vertical bars will match the height of the argument, whereas with \norm{M^\perp} the bars do not grow with the height of the argument but instead are the default height, and \norm[SIZE COMMAND]{M^\perp} also gives bars that do not grow but are set to the size given in the SIZE COMMAND, e.g., \Bigg.

\vert
     Single line vertical bar (ordinary). Similar: double-line vertical bar \Vert. For such that, as in the definition of a set, use \mid because it is a relation.

     For absolute value you can use the mathtools package and add \DeclarePairedDelimiter\abs{\lvert}{\rvert} to your preamble. This gives you three command variants for single-line vertical bars that are correctly horizontally spaced: if in the document body you write the starred version $\abs*{\frac{22}{7}}$ then the height of the vertical bars will match the height of the argument, whereas with \abs{\frac{22}{7}} the bars do not grow with the height of the argument but instead are the default height, and \abs[SIZE COMMAND]{\frac{22}{7}} also gives bars that do not grow but are set to the size given in the SIZE COMMAND, e.g., \Bigg.

\wedge
     Logical and (binary).  Synonym: \land.  See also logical or \vee. Similar: variable-sized operator \bigwedge.

\wp
     Weierstrass p (ordinary).

\wr
     Wreath product (binary).

\Xi
     Upper case Greek letter (ordinary).

\xi
     Lower case Greek letter (ordinary).

\zeta
     Lower case Greek letter (ordinary).

Math functions
==============

These commands produce roman function names in math mode with proper spacing.

\arccos
     \arccos

\arcsin
     \arcsin

\arctan
     \arctan

\arg
     \arg

\bmod
     Binary modulo operator (x \bmod y)

\cos
     \cos

\cosh
     \cosh

\cot
     \cot

\coth
     \coth

\csc
     \csc

\deg
     \deg

\det
     \det

\dim
     \dim

\exp
     \exp

\gcd
     \gcd

\hom
     \hom

\inf
     \inf

\ker
     \ker

\lg
     \lg

\lim
     \lim

\liminf
     \liminf

\limsup
     \limsup

\ln
     \ln

\log
     \log

\max
     \max

\min
     \min

\pmod
     parenthesized modulus, as in (\pmod 2^n - 1)

\Pr
     \Pr

\sec
     \sec

\sin
     \sin

\sinh
     \sinh

\sup
     sup

\tan
     \tan

\tanh
     \tanh

Math accents
============

LaTeX provides a variety of commands for producing accented letters in math.  These are different from accents in normal text (see Accents).

\acute
     Math acute accent: \acutex.

\bar
     Math bar-over accent: \barx.

\breve
     Math breve accent: \brevex.

\check
     Math háček (check) accent: \checkx.

\ddot
     Math dieresis accent: \ddotx.

\dot
     Math dot accent: \dotx.

\grave
     Math grave accent: \gravex.

\hat
     Math hat (circumflex) accent: \hatx.

\imath
     Math dotless i.

\jmath
     Math dotless j.

\mathring
     Math ring accent: x̊.

\tilde
     Math tilde accent: \tildex.

\vec
     Math vector symbol: \vecx.

\widehat
     Math wide hat accent: \widehatx+y.

\widetilde
     Math wide tilde accent: \widetildex+y.

Spacing in math mode
====================

In a math environment, LaTeX ignores the spaces that you use in the source, and instead puts in the spacing according to the normal rules for mathematics texts.

Many math mode spacing definitions are expressed in terms of the math unit mu given by 1 em = 18 mu, where the em is taken from the current math symbols family (see Units of length). LaTeX provides the following commands for use in math mode:

\;
     Normally 5.0mu plus 5.0mu.  The longer name is \thickspace.  Math mode only.

\:
\>
     Normally 4.0mu plus 2.0mu minus 4.0mu.  The longer name is \medspace.  Math mode only.

\,
     Normally 3mu.  The longer name is \thinspace.  This can be used in both math mode and text mode.

\!
     A negative thin space. Normally -3mu.  Math mode only.

\quad
     This is 18mu, that is, 1em. This is often used for space surrounding equations or expressions, for instance for the space between two equations inside a displaymath environment.  It is available in both text and math mode.

\qquad
     A length of 2 quads, that is, 36mu = 2em.  It is available in both text and math mode.

In this example a thinspace separates the function from the infinitesimal.

     \int_0^1 f(x)\,dx

Math miscellany
===============

\*
     A ``discretionary'' multiplication symbol, at which a line break is allowed.

\cdots
     A horizontal ellipsis with the dots raised to the center of the line.

\ddots
     A diagonal ellipsis: \ddots.

\frac{num}{den}
     Produces the fraction num divided by den.

\left DELIM1 ... \right DELIM2
     The two delimiters need not match; . acts as a null delimiter, producing no output.  The delimiters are sized according to the math in between.  Example: \left( \sum_i=1^10 a_i \right].

\overbrace{TEXT}
     Generates a brace over TEXT. For example, \overbracex+\cdots+x^k \rm\;times.

\overline{TEXT}
     Generates a horizontal line over TEX. For example, \overlinex+y.

\sqrt[ROOT]{arg}
     Produces the representation of the square root of ARG.  The optional argument ROOT determines what root to produce.  For example, the cube root of x+y would be typed as $\sqrt[3]{x+y}$.

\stackrel{TEXT}{RELATION}
     Puts TEXT above RELATION.  For example, \stackrel{f}{\longrightarrow}.

\underbrace{math}
     Generates MATH with a brace underneath.

\underline{text}
     Causes TEXT, which may be either math mode or not, to be underlined.  The line is always below the text, taking account of descenders.

\vdots
     Produces a vertical ellipsis.

Modes
*****

When LaTeX is processing your input text, it is always in one of three modes:

  * Paragraph mode

  * Math mode

  * Left-to-right mode, called LR mode for short

Mode changes occur only when entering or leaving an environment, or when LaTeX is processing the argument of certain text-producing commands.

Paragraph mode is the most common; it's the one LaTeX is in when processing ordinary text.  In this mode, LaTeX breaks the input text into lines and breaks the lines into pages.

LaTeX is in math mode when it's generating a mathematical formula, either displayed math or within a line.

In LR mode, as in paragraph mode, LaTeX considers the output that it produces to be a string of words with spaces between them. However, unlike paragraph mode, LaTeX keeps going from left to right; it never starts a new line in LR mode.  Even if you put a hundred words into an \mbox, LaTeX would keep typesetting them from left to right inside a single box (and then most likely complain because the resulting box was too wide to fit on the line). LaTeX is in LR mode when it starts making a box with an \mbox command.  You can get it to enter a different mode inside the box---for example, you can make it enter math mode to put a formula in the box.

There are also several text-producing commands and environments for making a box that put LaTeX into paragraph mode.  The box made by one of these commands or environments will be called a parbox. When LaTeX is in paragraph mode while making a box, it is said to be in ``inner paragraph mode'' (no page breaks).  Its normal paragraph mode, which it starts out in, is called ``outer paragraph mode''.

Page styles
***********

The \documentclass command determines the size and position of the page's head and foot.  The page style determines what goes in them.

\maketitle
==========

The \maketitle command generates a title on a separate title page---except in the article class, where the title is placed at the top of the first page.  Information used to produce the title is obtained from the following declarations:

\author{NAME \and NAME2}
     The \author command declares the document author(s), where the argument is a list of authors separated by \and commands.  Use \\ to separate lines within a single author's entry---for example, to give the author's institution or address.

\date{TEXT}
     The \date command declares TEXT to be the document's date.  With no \date command, the current date (see \today) is used.

\thanks{TEXT}
     The \thanks command produces a \footnote to the title, usually used for credit acknowledgements.

\title{TEXT}
     The \title command declares TEXT to be the title of the document.  Use \\ to force a line break, as usual.

\pagenumbering
==============

Synopsis:

     \pagenumbering{STYLE}

Specifies the style of page numbers, according to STYLE; also resets the page number to 1.  The STYLE argument is one of the following:

arabic
     arabic numerals

roman
     lowercase Roman numerals

Roman
     uppercase Roman numerals

alph
     lowercase letters

Alph
     uppercase letters

\pagestyle
==========

Synopsis:

     \pagestyle{STYLE}

The \pagestyle command specifies how the headers and footers are typeset from the current page onwards.  Values for STYLE:

plain
     Just a plain page number.

empty
     Empty headers and footers, e.g., no page numbers.

headings
     Put running headers on each page.  The document style specifies what goes in the headers.

myheadings
     Custom headers, specified via the \markboth or the \markright commands.

Here are the descriptions of \markboth and \markright:

\markboth{LEFT}{RIGHT}
     Sets both the left and the right heading.  A ``left-hand heading'' (LEFT) is generated by the last \markboth command before the end of the page, while a ``right-hand heading'' (RIGHT) is generated by the first \markboth or \markright that comes on the page if there is one, otherwise by the last one before the page.

\markright{RIGHT}
     Sets the right heading, leaving the left heading unchanged.

\thispagestyle{STYLE}
=====================

The \thispagestyle command works in the same manner as the \pagestyle command (see previous section) except that it changes to STYLE for the current page only.

Spaces
******

LaTeX has many ways to produce white (or filled) space.

\hspace
=======

Synopsis:

     \hspace{LENGTH}
     \hspace*{LENGTH}

Add the horizontal space given by LENGTH.  The LENGTH is a rubber length, that is, it may contain a plus or minus component, in any unit that LaTeX understands (see Lengths).

This command can add both positive and negative space; adding negative space is like backspacing.

Normally when TeX breaks a paragraph into lines it discards white space (glues and kerns) that would come at the start of a line, so you get an inter-word space or a line break between words but not both. This command's starred version \hspace*{..} puts a non-discardable invisible item in front of the space, so the space appears in the output.

This example make a one-line paragraph that puts Name: an inch from the right margin.

     \noindent\makebox[\linewidth]{\hspace{\fill}Name:\hspace{1in}}

\hfill
======

Produce a rubber length which has no natural space but can stretch horizontally as far as needed (see Lengths).

The command \hfill is equivalent to \hspace{\fill}.  For space that does not disappear at line breaks use \hspace*{\fill} instead (see \hspace).

\(SPACE) and \@
===============

old name

Mark a punctuation character, typically a period, as either ending a sentence or as ending an abbreviation.

By default, in justifying a line LaTeX adjusts the space after a sentence-ending period (or a question mark, exclamation point, comma, or colon) more than the space between words (see \frenchspacing). LaTeX assumes that the period ends a sentence unless it is preceded by a capital letter, in which case it takes that period for part of an abbreviation.  Note that if a sentence-ending period is immediately followed by a right parenthesis or bracket, or right single or double quote, then the intersentence space follows that parenthesis or quote.

If you have a period ending an abbreviation whose last letter is not a capital letter, and that abbreviation is not the last word in the sentence, then follow that period with a backslash-space (\ ) or a tie (~).  Examples are Nat.\ Acad.\ Science, and Mr.~Bean, and (manure, etc.)\ for sale.

For other use of \ , see also \(SPACE) after CS.

In the opposite situation, if you have a capital letter followed by a period that ends the sentence, then put \@ on the left of that period.  For example, book by the MAA\@. will have intersentence spacing after the period.

In contrast, putting \@ on the right of a period tells TeX that the period does not end the sentence.  In the example reserved words (if, then, etc.\@) are different, TeX will put interword space after the closing parenthesis (note that \@ is before the parenthesis).

\ after a control sequence
==========================

The \  command is often used after control sequences to keep them from gobbling the space that follows, as in \TeX\ is a nice system.  And, under normal circumstances \tab and \newline are equivalent to \ . For other use of \ , see also \(SPACE) and \@.

Some people prefer to use {} for the same purpose, as in \TeX{} is a nice system. This has the advantage that you can always write it the same way, like \TeX{}, whether it is followed by a space or by a punctuation mark. Please compare:

     \TeX\ is a nice system. \TeX, a nice system.

     \TeX{} is a nice system. \TeX{}, a nice system.

When you define user commands (see \newcommand & \renewcommand) you can prevent the space gobbling after the command by using the package xspace and inserting \xspace at the end of the definition For instance:

     \documentclass{minimal}
     \usepackage{xspace}
     \newcommand*{\Loup}{Grand Cric\xspace}
     \begin{document}
     Que le \Loup me croque !
     \end{document}

A quick hack to use \xspace for existing command is as follows:

     \documentclass{minimal}
     \usepackage{xspace}
     \newcommand*{\SansXspaceTeX}{}
     \let\SansXspaceTeX\TeX
     \renewcommand{\TeX}{\SansXspaceTeX\xspace}
     \begin{document}
     \TeX is a nice system.
     \end{document}

\frenchspacing
==============

This declaration (from Plain TeX) causes LaTeX to treat intersentence spacing in the same way as interword spacing.

In justifying the text in a line, some typographic traditions, including English, prefer to adjust the space between sentences (or after other punctuation marks) more than the space between words.  Following this declaration, all spaces are instead treated equally.

Revert to the default behavior by declaring \nonfrenchspacing.

\thinspace: Insert 1/6em
========================

\thinspace produces an unbreakable and unstretchable space that is 1/6 of an em.  This is the proper space to use between nested quotes, as in '''. Abuse, which is a thin space in Texinfo.

\/: Insert italic correction
============================

The \/ command produces an italic correction.  This is a small space defined by the font designer for a given character, to avoid the character colliding with whatever follows.  The italic f character typically has a large italic correction value.

If the following character is a period or comma, it's not necessary to insert an italic correction, since those punctuation symbols have a very small height.  However, with semicolons or colons, as well as normal letters, it can help. Compare f: f; (in the TeX output, the `f's are nicely separated) with f: f;.

When changing fonts with commands such as \textit{italic text} or {\itshape italic text}, LaTeX will automatically insert an italic correction if appropriate (see Font styles).

Despite the name, roman characters can also have an italic correction.  Compare pdfTeX (in the TeX output, there is a small space after the `f') with pdfTeX.

There is no concept of italic correction in math mode; spacing is done in a different way.

\hrulefill \dotfill
===================

Produce an infinite rubber length (see Lengths) filled with a horizontal rule (that is, a line) or with dots, instead of just white space.

When placed between blank lines this example creates a paragraph that is left and right justified, where the space in the middle is filled with evenly spaced dots.

     \noindent Jack Aubrey\dotfill Melbury Lodge

To make the rule or dots go to the line's end use \null at the start or end.

To change the rule's thickness, copy the definition and adjust it, as with \renewcommand{\hrulefill}{\leavevmode\leaders\hrule height 1pt\hfill\kern\z@}, which changes the default thickness of 0.4pt to 1pt.  Similarly, adjust the dot spacing as with \renewcommand{\dotfill}{\leavevmode\cleaders\hb@xt@ 1.00em{\hss .\hss }\hfill\kern\z@}, which changes the default length of 0.33em to 1.00em.

\addvspace
==========

\addvspace{LENGTH}

Add a vertical space of height LENGTH, which is a rubber length (see Lengths).  However, if vertical space has already been added to the same point in the output by a previous \addvspace command then this command will not add more space than what is needed to make the natural length of the total vertical space equal to LENGTH.

Use this command to adjust the vertical space above or below an environment that starts a new paragraph.  (For instance, a Theorem environment is defined to begin and end in \addvspace{..} so that two consecutive Theorem's are separated by one vertical space, not two.)

This command is fragile (see \protect).

The error Something's wrong--perhaps a missing \item means that you were not in vertical mode when you invoked this command; one way to change that is to precede this command with a \par command.

\bigskip \medskip \smallskip
============================

These commands produce a given amount of space, specified by the document class.

\bigskip
     The same as \vspace{\bigskipamount}, ordinarily about one line space, with stretch and shrink (the default for the book and article classes is 12pt plus 4pt minus 4pt).

\medskip
     The same as \vspace{\medskipamount}, ordinarily about half of a line space, with stretch and shrink (the default for the book and article classes is 6pt plus 2pt minus 2pt).

\smallskip
     The same as \vspace{\smallskipamount}, ordinarily about a quarter of a line space, with stretch and shrink (the default for the book and article classes is 3pt plus 1pt minus 1pt).

\vfill
======

End the current paragraph and insert a vertical rubber length (see Lengths) that is infinite, so it can stretch or shrink as far as needed.

It is often used in the same way as \vspace{\fill}, except that \vfill ends the current paragraph, whereas \vspace{\fill} adds the infinite vertical space below its line irrespective of the paragraph structure.  In both cases that space will disappear at a page boundary; to circumvent this see \vspace.

In this example the page is filled, so the top and bottom lines contain the text Lost Dog! and the third Lost Dog! is exactly halfway between them.

     \begin{document}
     Lost Dog!
     \vfill
     Lost Dog!
     \vfill
     Lost Dog!
     \end{document}

\vspace{LENGTH}
===============

Synopsis, one of these two:

     \vspace{LENGTH}
     \vspace*{LENGTH}

Add the vertical space LENGTH.  This can be negative or positive, and is a rubber length (see Lengths).

LaTeX removes the vertical space from \vfill at a page break, that is, at the top or bottom of a page.  The starred version \vspace*{..} causes the space to stay.

In this example the two questions will be evenly spaced vertically on the page, with at least one inch of space below each.

     \begin{document}
     1) Who put the bomp in the bomp bah bomp bah bomp?
     \vspace{1in plus 1fill}

     2) Who put the ram in the rama lama ding dong?
     \vspace{1in plus 1fill}
     \end{document}

Boxes
*****

All the predefined length parameters (see Predefined lengths) can be used in the arguments of the box-making commands.

\mbox{TEXT}
===========

The \mbox command creates a box just wide enough to hold the text created by its argument.  The TEXT is not broken into lines, so it can be used to prevent hyphenation.

\fbox and \framebox
===================

Synopses:

     \fbox{TEXT}
     \framebox[WIDTH][POSITION]{TEXT}

The \fbox and \framebox commands are like \mbox, except that they put a frame around the outside of the box being created.

In addition, the \framebox command allows for explicit specification of the box width with the optional WIDTH argument (a dimension), and positioning with the optional POSITION argument.

Both commands produce a rule of thickness \fboxrule (default .4pt), and leave a space of \fboxsep (default 3pt) between the rule and the contents of the box.

See \framebox (picture), for the \framebox command in the picture environment.

lrbox
=====

\begin{lrbox}{cmd} text \end{lrbox}

This is the environment form of \sbox.

The text inside the environment is saved in the box cmd, which must have been declared with \newsavebox.

\makebox
========

Synopsis:

     \makebox[WIDTH][POSITION]{TEXT}

The \makebox command creates a box just wide enough to contain the TEXT specified.  The width of the box can be overridden by the optional WIDTH argument.  The position of the text within the box is determined by the optional POSITION argument, which may take the following values:

c
     Centered (default).

l
     Flush left.

r
     Flush right.

s
     Stretch (justify) across entire WIDTH; TEXT must contain stretchable space for this to work.

\makebox is also used within the picture environment see \makebox (picture).

\parbox
=======

Synopsis:

     \parbox[POSITION][HEIGHT][INNER-POS]{WIDTH}{TEXT}

The \parbox command produces a box whose contents are created in paragraph mode.  It should be used to make a box small pieces of text, with nothing fancy inside.  In particular, you shouldn't use any paragraph-making environments inside a \parbox argument.  For larger pieces of text, including ones containing a paragraph-making environment, you should use a minipage environment (see minipage).

\parbox has two mandatory arguments:

width
     the width of the parbox;

text
     the text that goes inside the parbox.

The optional POSITION argument allows you to align either the top or bottom line in the parbox with the baseline of the surrounding text (default is top).

The optional HEIGHT argument overrides the natural height of the box.

The INNER-POS argument controls the placement of the text inside the box, as follows; if it is not specified, POSITION is used.

t
     text is placed at the top of the box.

c
     text is centered in the box.

b
     text is placed at the bottom of the box.

s
     stretch vertically; the text must contain vertically stretchable space for this to work.

\raisebox
=========

Synopsis:

     \raisebox{distance}[HEIGHT][DEPTH]{text}

The \raisebox command raises or lowers TEXT.  The first mandatory argument specifies how high TEXT is to be raised (or lowered if it is a negative amount).  TEXT itself is processed in LR mode.

The optional arguments HEIGHT and DEPTH are dimensions. If they are specified, LaTeX treats TEXT as extending a certain distance above the baseline (height) or below (depth), ignoring its natural height and depth.

\savebox
========

Synopsis:

     \savebox{\BOXCMD}[WIDTH][POS]{TEXT}

This command typeset TEXT in a box just as with \makebox (see \makebox), except that instead of printing the resulting box, it saves it in the box labeled \BOXCMD, which must have been declared with \newsavebox (see \newsavebox).

\sbox{\BOXCMD}{TEXT}
====================

Synopsis:

     \sbox{\BOXCMD}{TEXT}

\sbox types TEXT in a box just as with \mbox (see \mbox) except that instead of the resulting box being included in the normal output, it is saved in the box labeled \BOXCMD.  \BOXCMD must have been previously declared with \newsavebox (see \newsavebox).

\usebox{\BOXCMD}
================

Synopsis:

     \usebox{\BOXCMD}

\usebox produces the box most recently saved in the bin \BOXCMD by a \savebox command (see \savebox).

Special insertions
******************

LaTeX provides commands for inserting characters that have a special meaning do not correspond to simple characters you can type.

Reserved characters
===================

The following characters play a special role in LaTeX and are called ``reserved characters'' or ``special characters''.

     # $ % & ~ _ ^ \ { }

Whenever you write one of these characters into your file, LaTeX will do something special.  If you simply want the character to be printed as itself, include a \ in front of the character.  For example, \$ will produce $ in your output.

One exception to this rule is \ itself, because \\ has its own special (context-dependent) meaning.  A roman \ is produced by typing $\backslash$ in your file, and a typewriter \ is produced by using \ in a verbatim command (see verbatim).

Also, \~ and \^ place tilde and circumflex accents over the following letter, as in õ and ô (see Accents); to get a standalone ~ or ^, you can again use a verbatim command.

Finally, you can access any character of the current font once you know its number by using the \symbol command. For example, the visible space character used in the \verb* command has the code decimal 32, so it can be typed as \symbol{32}.

You can also specify octal numbers with ' or hexadecimal numbers with ", so the previous example could also be written as \symbol{'40} or \symbol{"20}.

Text symbols
============

LaTeX provides commands to generate a number of non-letter symbols in running text.  Some of these, especially the more obscure ones, are not available in OT1; you may need to load the textcomp package.

\copyright
\textcopyright
     The copyright symbol, ©.

\dag
     The dagger symbol (in text).

\ddag
     The double dagger symbol (in text).

\LaTeX
     The LaTeX logo.

\LaTeXe
     The LaTeX2e logo.

\guillemotleft («)
\guillemotright (»)
\guilsinglleft (‹)
\guilsinglright (›)
     Double and single angle quotation marks, commonly used in French: «, », ‹, ›.

\ldots
\dots
\textellipsis
     An ellipsis (three dots at the baseline): `...'.  \ldots and \dots also work in math mode.

\lq
     Left (opening) quote: `.

\P
\textparagraph
     Paragraph sign (pilcrow).

\pounds
\textsterling
     English pounds sterling: £.

\quotedblbase („)
\quotesinglbase (‚)
     Double and single quotation marks on the baseline: „ and ‚.

\rq
     Right (closing) quote: '.

\S
     Section symbol.

\TeX
     The TeX logo.

\textasciicircum
     ASCII circumflex: ^.

\textasciitilde
     ASCII tilde: ~.

\textasteriskcentered
     Centered asterisk: *.

\textbackslash
     Backslash: \.

\textbar
     Vertical bar: |.

\textbardbl
     Double vertical bar.

\textbigcircle
     Big circle symbol.

\textbraceleft
     Left brace: {.

\textbraceright
     Right brace: }.

\textbullet
     Bullet: *.

\textcircled{LETTER}
     LETTER in a circle, as in ®.

\textcompwordmark
\textcapitalwordmark
\textascenderwordmark
     Composite word mark (invisible).  The \textcapital... form has the cap height of the font, while the \textascender... form has the ascender height.

\textdagger
     Dagger: \dag.

\textdaggerdbl
     Double dagger: \ddag.

\textdollar (or $)
     Dollar sign: $.

\textemdash (or ---)
     Em-dash: --- (for punctuation).

\textendash (or --)
     En-dash: -- (for ranges).

\texteuro
     The Euro symbol: €.

\textexclamdown (or !`)
     Upside down exclamation point: ¡.

\textgreater
     Greater than: >.

\textless
     Less than: <.

\textleftarrow
     Left arrow.

\textordfeminine
\textordmasculine
     Feminine and masculine ordinal symbols: ª, º.

\textperiodcentered
     Centered period: \cdot.

\textquestiondown (or ?`)
     Upside down question mark: ¿.

\textquotedblleft (or ``)
     Double left quote: ``.

\textquotedblright (or ')
     Double right quote: ''.

\textquoteleft (or `)
     Single left quote: `.

\textquoteright (or ')
     Single right quote: '.

\textquotestraightbase
\textquotestraightdblbase
     Single and double straight quotes on the baseline.

\textregistered
     Registered symbol: ®.

\textrightarrow
     Right arrow.

\textthreequartersemdash
     ``Three-quarters'' em-dash, between en-dash and em-dash.

\texttrademark
     Trademark symbol: ^\hboxTM.

\texttwelveudash
     ``Two-thirds'' em-dash, between en-dash and em-dash.

\textunderscore
     Underscore: _.

\textvisiblespace
     Visible space symbol.

Accents
=======

LaTeX has wide support for many of the world's scripts and languages, through the babel package and related support.  This section does not attempt to cover all that support.  It merely lists the core LaTeX commands for creating accented characters.

The \capital... commands produce alternative forms for use with capital letters.  These are not available with OT1.

\"
\capitaldieresis
     Produces an umlaut (dieresis), as in ö.

\'
\capitalacute
     Produces an acute accent, as in ó.  In the tabbing environment, pushes current column to the right of the previous column (see tabbing).

\.
     Produces a dot accent over the following, as in ȯ.

\=
\capitalmacron
     Produces a macron (overbar) accent over the following, as in ō.

\^
\capitalcircumflex
     Produces a circumflex (hat) accent over the following, as in ô.

\`
\capitalgrave
     Produces a grave accent over the following, as in ò.  In the tabbing environment, move following text to the right margin (see tabbing).

\~
\capitaltilde
     Produces a tilde accent over the following, as in ñ.

\b
     Produces a bar accent under the following, as in o̱. See also \underbar hereinafter.

\c
\capitalcedilla
     Produces a cedilla accent under the following, as in ç.

\d
\capitaldotaccent
     Produces a dot accent under the following, as in ọ.

\H
\capitalhungarumlaut
     Produces a long Hungarian umlaut accent over the following, as in ő.

\i
     Produces a dotless i, as in `ı'.

\j
     Produces a dotless j, as in `ȷ'.

\k
\capitalogonek
     Produces a letter with ogonek, as in `ǫ'.  Not available in the OT1 encoding.

\r
\capitalring
     Produces a ring accent, as in `o̊'.

\t
\capitaltie
\newtie
\capitalnewtie
     Produces a tie-after accent, as in `o͡o'.  The \newtie form is centered in its box.

\u
\capitalbreve
     Produces a breve accent, as in `ŏ'.

\underbar
     Not exactly an accent, this produces a bar under the argument text. The argument is always processed in horizontal mode.  The bar is always a fixed position under the baseline, thus crossing through descenders.  See also \underline in Math miscellany. See also \b above.

\v
\capitalcaron
     Produces a háček (check, caron) accent, as in `ǒ'.

Non-English characters
======================

Here are the basic LaTeX commands for inserting characters commonly used in languages other than English.

\aa
\AA
     å and Å.

\ae
\AE
     æ and Æ.

\dh
\DH
     Icelandic letter eth: ð and Ð.

\dj
\DJ
     Crossed d and D, a.k.a. capital and small letter d with stroke.

\ij
\IJ
     ij and IJ (except somewhat closer together than appears here).

\l
\L
     ł and Ł.

\ng
\NG
     Latin letter eng, also used in phonetics.

\o
\O
     ø and Ø.

\oe
\OE
     œ and Œ.

\ss
\SS
     ß and SS.

\th
\TH
     Icelandic letter thorn: þ and Þ.

\rule
=====

Synopsis:

     \rule[RAISE]{WIDTH}{THICKNESS}

The \rule command produces rules, that is, lines or rectangles.  The arguments are:

raise
     How high to raise the rule (optional).

width
     The length of the rule (mandatory).

thickness
     The thickness of the rule (mandatory).

\today
======

The \today command produces today's date, in the format MONTH DD, YYYY; for example, `July 4, 1976'. It uses the predefined counters \day, \month, and \year (see \day \month \year) to do this.  It is not updated as the program runs.

The datetime package, among others, can produce a wide variety of other date formats.

Splitting the input
*******************

A large document requires a lot of input.  Rather than putting the whole input in a single large file, it's more efficient to split it into several smaller ones.  Regardless of how many separate files you use, there is one that is the root file; it is the one whose name you type when you run LaTeX.

See filecontents, for an environment that allows bundling an external file to be created with the main document.

\include
========

Synopsis:

     \include{FILE}

If no \includeonly command is present, the \include command executes \clearpage to start a new page (see \clearpage), then reads FILE, then does another \clearpage.

Given an \includeonly command, the \include actions are only run if FILE is listed as an argument to \includeonly.  See the next section.

The \include command may not appear in the preamble or in a file read by another \include command.

\includeonly
============

Synopsis:

     \includeonly{FILE1,FILE2,...}

The \includeonly command controls which files will be read by subsequent \include commands.  The list of filenames is comma-separated. Each FILE must exactly match a filename specified in a \include command for the selection to be effective.

This command can only appear in the preamble.

\input
======

Synopsis:

     \input{FILE}

The \input command causes the specified FILE to be read and processed, as if its contents had been inserted in the current file at that point.

If FILE does not end in .tex (e.g., foo or foo.bar), it is first tried with that extension (foo.tex or foo.bar.tex).  If that is not found, the original FILE is tried (foo or foo.bar).

Front/back matter
*****************

Tables of contents
==================

A table of contents is produced with the \tableofcontents command.  You put the command right where you want the table of contents to go; LaTeX does the rest for you.  A previous run must have generated a .toc file.

The \tableofcontents command produces a heading, but it does not automatically start a new page.  If you want a new page after the table of contents, write a \newpage command after the \tableofcontents command.

The analogous commands \listoffigures and \listoftables produce a list of figures and a list of tables (from .lof and .lot files), respectively.  Everything works exactly the same as for the table of contents.

The command \nofiles overrides these commands, and prevents any of these lists from being generated.

\addcontentsline
----------------

The \addcontentsline{EXT}{UNIT}{TEXT} command adds an entry to the specified list or table where:

ext
     The extension of the file on which information is to be written, typically one of: toc (table of contents), lof (list of figures), or lot (list of tables).

unit
     The name of the sectional unit being added, typically one of the following, matching the value of the EXT argument:

     toc
          The name of the sectional unit: part, chapter, section, subsection, subsubsection.

     lof
          For the list of figures.

     lot
          For the list of tables.

entry
     The text of the entry.

What is written to the .EXT file is the command \contentsline{UNIT}{NAME}.

\addtocontents
--------------

The \addtocontents{EXT}{TEXT} command adds text (or formatting commands) directly to the .EXT file that generates the table of contents or lists of figures or tables.

ext
     The extension of the file on which information is to be written, typically one of: toc (table of contents), lof (list of figures), or lot (list of tables).

text
     The text to be written.

Glossaries
==========

The command \makeglossary enables creating glossaries.

The command \glossary{TEXT} writes a glossary entry for TEXT to an auxiliary file with the .glo extension.

Specifically, what gets written is the command \glossaryentry{TEXT}{PAGENO}, where PAGENO is the current \thepage value.

The glossary package on CTAN provides support for fancier glossaries.

Indexes
=======

The command \makeindex enables creating indexes.  Put this in the preamble.

The command \index{TEXT} writes an index entry for TEXT to an auxiliary file with the .idx extension.

Specifically, what gets written is the command \indexentry{TEXT}{PAGENO}, where PAGENO is the current \thepage value.

To generate a index entry for `bar' that says `See foo', use a vertical bar: \index{bar|see{foo}}.  Use seealso instead of see to make a `See also' entry.

The text `See' is defined by the macro \seename, and `See also' by the macro \alsoname.  These can be redefined for other languages.

The generated .idx file is then sorted with an external command, usually either makeindex (http://mirror.ctan.org/indexing/makeindex) or (the multi-lingual) xindy (http://xindy.sourceforge.net). This results in a .ind file, which can then be read to typeset the index.

The index is usually generated with the \printindex command. This is defined in the makeidx package, so \usepackage{makeidx} needs to be in the preamble.

The rubber length \indexspace is inserted before each new letter in the printed index; its default value is 10pt plus5pt minus3pt.

The showidx package causes each index entries to be shown in the margin on the page where the entry appears.  This can help in preparing the index.

The multind package supports multiple indexes.  See also the TeX FAQ entry on this topic, http://www.tex.ac.uk/cgi-bin/texfaq2html?label=multind.

Letters
*******

Synopsis:

     \documentclass{letter}
     \address{SENDER ADDRESS}
     \signature{SENDER NAME}
     \begin{document}
     \begin{letter}{RECIPIENT ADDRESS}
     \opening{SALUTATION}
       LETTER BODY
     \closing{CLOSING TEXT}
     \end{letter}
       ...  more letters ...
     \end{document}

Produce one or more letters.

Each letter is in a separate letter environment, whose argument RECIPIENT ADDRESS often contains multiple lines separated with a double backslash (\\).  For example, you might have:

      \begin{letter}{Mr. Joe Smith \\
           2345 Princess St. \\
           Edinburgh, EH1 1AA}
        ...
      \end{letter}

The start of the letter environment resets the page number to 1, and the footnote number to 1 also.

The SENDER ADDRESS and SENDER NAME are common to all of the letters, whether there is one or more, so these are best put in the preamble.  As with the recipient address, often SENDER ADDRESS contains multiple lines separated by a double backslash (\\).  LaTeX will put the SENDER NAME under the closing, after a vertical space for the traditional hand-written signature; it also can contain multiple lines.

Each letter environment begins with a required \opening command such as \opening{Dear Madam or Sir:}.  The LETTER BODY text is ordinary LaTeX so it can contain everything from from enumerated lists to displayed math, except that commands such as \chapter that make no sense in a letter are turned off.  Each letter environment typically ends with a \closing command such as \closing{Yours,}.

Additional material may come after the \closing.  You can say who is receiving a copy of the letter with a command like \cc{the Boss \\ the Boss's Boss}.  There's a similar \encl command for a list of enclosures.  And, you can add a postscript with \ps.

LaTeX's default is to indent the signature and the \closing above it by a length of \longindentation.  By default this is 0.5\textwidth. To make them flush left, put \setlength{\longindentation}{0em} in your preamble.

To set a fixed date use something like \renewcommand{\today}{2015-Oct-12}.  If put in your preamble then it will apply to all the letters.

This example shows only one letter environment.  The three lines marked as optional are typically omitted.

     \documentclass{letter}
     \address{Sender's street \\ Sender's town}
     \signature{Sender's name \\ Sender's title}
     % optional: \location{Mailbox 13}
     % optional: \telephone{(102) 555-0101}
     \begin{document}
     \begin{letter}{Recipient's name \\ Recipient's address}
     \opening{Sir:}
     % optional: \thispagestyle{firstpage}
     I am not interested in entering a business arrangement with you.
     \closing{Your most humble, etc.,}
     \end{letter}
     \end{document}

These commands are used with the letter class.

\address
========

Synopsis:

     \address{SENDERS ADDRESS}

Specifies the return address as it appears on the letter and on the envelope.  Separate multiple lines in SENDERS ADDRESS with a double backslash \\.

Because it can apply to multiple letters this declaration is often put in the preamble.  However, it can go anywhere, including inside an individual letter environment.

This command is optional: without the \address declaration the letter is formatted with some blank space on top, for copying onto pre-printed letterhead paper.  (see Overview, for details on your local implementation.)  With the \address declaration, it is formatted as a personal letter.

Here is an example.

     \address{Stephen Maturin \\
              The Grapes of the Savoy}

\cc
===

Synopsis:

     \cc{FIRST NAME \\
         .. }

Produce a list of names to which copies of the letter were sent.  This command is optional.  If it appears then typically it comes after \closing.  Separate multiple lines with a double backslash \\.

     \cc{President \\
         Vice President}

\closing
========

Synopsis:

     \closing{text}

Usually at the end of a letter, above the handwritten signature, there is a \closing (although this command is optional).  For example,

     \closing{Regards,}

\encl
=====

Synopsis:

     \encl{FIRST ENCLOSED OBJECT \\
           .. }

Produce a list of things included with the letter. This command is optional; when it is used, it typically is put after \closing. Separate multiple lines with a double backslash \\.

     \encl{License \\
            Passport }

\location
=========

Synopsis:

     \location{TEXT}

The TEXT appears centered at the bottom of the each page.  It only appears if the page style is firstpage.

\makelabels
===========

Synopsis:

     \makelabels

Create a sheet of address labels from the recipient addresses, one for each letter. This sheet will be output before the letters, with the idea that you can copy it to a sheet of peel-off labels.  This command goes in the preamble.

Customize the labels by redefining the commands \startlabels, \mlabel, and \returnaddress in the preamble.  The command \startlabels sets the width, height, number of columns, etc., of the page onto which the labels are printed.  The command \mlabel{SENDER ADDRESS}{RECIPIENT ADDRESS} produces the two labels (or one, if you choose to ignore the SENDER ADDRESS). The SENDER ADDRESS is the value returned by the macro \returnaddress while RECIPIENT ADDRESS is the value passed in the argument to the letter environment.  By default \mlabel ignores the first argument, the SENDER ADDRESS.

\name
=====

Synopsis:

     \name{NAME}

Sender's name, used for printing on the envelope together with the return address.

\opening
========

Synopsis:

     \opening{TEXT}

This command is required.  It starts a letter, following the \begin{letter}{..}. The mandatory argument TEXT is the text that starts your letter.  For instance:

     \opening{Dear John:}

\ps
===

Synopsis:

     \ps{TEXT}

Add a postscript.  This command is optional and usually is used after \closing.

     \ps{P.S.  After you have read this letter, burn it. Or eat it.}

\signature
==========

Synopsis:

     \signature{FIRST LINE \\
                 .. }

The sender's name.  This command is optional, although its inclusion is usual.

The argument text appears at the end of the letter, after the closing and after a vertical space for the traditional hand-written signature. Separate multiple lines with a double backslash \\.  For example:

     \signature{J Fred Muggs \\
                White House}

LaTeX's default for the vertical space from the \closing text down to the \signature text is 6\medskipamount, which is six times 0.7em.

This command is usually in the preamble, to apply to all the letters in the document.  To have it apply to one letter only, put it inside a letter environment and before the \closing.

You can include a graphic in the signature, for instance with \signature{\vspace{-6\medskipamount}\includegraphics{sig.png}\\ My name} (this requires writing \usepackage{graphicx} in the preamble).

\telephone
==========

Synopsis:

     \telephone{NUMBER}

The sender's telephone number.  This is typically in the preamble, where it applies to all letters.  This only appears if the firstpage pagestyle is selected.  If so, it appears on the lower right of the page.

Terminal input/output
*********************

\typein[CMD]{MSG}
=================

Synopsis:

     \typein[\CMD]{MSG}

\typein prints MSG on the terminal and causes LaTeX to stop and wait for you to type a line of input, ending with return.  If the optional \CMD argument is omitted, the typed input is processed as if it had been included in the input file in place of the \typein command.  If the \CMD argument is present, it must be a command name.  This command name is then defined or redefined to be the typed input.

\typeout{MSG}
=============

Synopsis:

     \typeout{MSG}

Prints msg on the terminal and in the log file. Commands in msg that are defined with \newcommand or \renewcommand (among others) are replaced by their definitions before being printed.

LaTeX's usual rules for treating multiple spaces as a single space and ignoring spaces after a command name apply to msg.  A \space command in msg causes a single space to be printed, independent of surrounding spaces.  A ^^J in msg prints a newline.

Command line
************

The input file specification indicates the file to be formatted; TeX uses .tex as a default file extension.  If you omit the input file entirely, TeX accepts input from the terminal.  You can also specify arbitrary LaTeX input by starting with a backslash. For example, this processes foo.tex without pausing after every error:

     latex '\nonstopmode\input foo.tex'

With many, but not all, implementations, command-line options can also be specified in the usual Unix way, starting with - or --.  For a list of those options, try latex --help.

If LaTeX stops in the middle of the document and gives you a * prompt, it is waiting for input.  You can type \stop (and return) and it will prematurely end the document.

See TeX engines, for other system commands invoking LaTeX.

Document templates
******************

Although not reference material, perhaps these document templates will be useful.  Additional template resources are listed at http://tug.org/interest.html#latextemplates.

beamer template
===============

The beamer class creates presentation slides.  It has a vast array of features, but here is a basic template:

\documentclass{beamer}

\title{Beamer Class template}
\author{Alex Author}
\date{July 31, 2007}

\begin{document}

\maketitle

% without [fragile], any {verbatim} code gets mysterious errors.
\begin{frame}[fragile]
 \frametitle{First Slide}

\begin{verbatim}
  This is \verbatim!
\end{verbatim}

\end{frame}

\end{document}

One web resource for this: http://robjhyndman.com/hyndsight/beamer/.

book template
=============

\documentclass{book}
\title{Book Class Template}
\author{Alex Author}

\begin{document}
\maketitle

\chapter{First}
Some text.

\chapter{Second}
Some other text.

\section{A subtopic}
The end.
\end{document}

tugboat template
================

TUGboat is the journal of the TeX Users Group, http://tug.org/TUGboat.

\documentclass{ltugboat}
\usepackage{graphicx}
\usepackage{ifpdf}
\ifpdf
\usepackage[breaklinks,hidelinks]{hyperref}
\else
\usepackage{url}
\fi

\title{Example \TUB\ article}

% repeat info for each author.
\author{First Last}
\address{Street Address \\ Town, Postal \\ Country}
\netaddress{user (at) example dot org}
\personalURL{http://example.org/~user/}

\begin{document}

\maketitle

\begin{abstract}
This is an example article for \TUB{}.
\end{abstract}

\section{Introduction}

This is an example article for \TUB, from
\url{http://tug.org/TUGboat/location.html}.

We recommend the \texttt{graphicx} package for image inclusions, and the
\texttt{hyperref} package for active urls in the \acro{PDF} output.
Nowadays \TUB\ is produced using \acro{PDF} files exclusively.

The \texttt{ltugboat} class provides these abbreviations and many more:

% verbatim blocks are often better in \small
\begin{verbatim}[\small]
\AllTeX \AMS \AmS \AmSLaTeX \AmSTeX \aw \AW
\BibTeX \CTAN \DTD \HTML
\ISBN \ISSN \LaTeXe
\Mc \mf \MFB \mtex \PCTeX \pcTeX
\PiC \PiCTeX \plain \POBox \PS
\SC \SGML \SliTeX \TANGLE \TB \TP
\TUB \TUG \tug
\UG \UNIX \VAX \XeT \WEB \WEAVE

\Dash \dash \vellipsis \bull \cents \Dag
\careof \thinskip

\acro{FRED} -> {\small[er] fred}  % please use!
\cs{fred}   -> \fred
\env{fred}  -> \begin{fred}
\meta{fred} -> <fred>
\nth{n}     -> 1st, 2nd, ...
\sfrac{3/4} -> 3/4
\booktitle{Book of Fred}
\end{verbatim}

For more information, see the ltubguid document at:
\url{http://mirror.ctan.org/macros/latex/contrib/tugboat}
(we recommend using \verb|mirror.ctan.org| for \CTAN\ references).

Email \verb|tugboat@tug.org| if problems or questions.

\bibliographystyle{plain}  % we recommend the plain bibliography style
\nocite{book-minimal}      % just making the bibliography non-empty
\bibliography{xampl}       % xampl.bib comes with BibTeX

\makesignature
\end{document}