LaTeX2e reference manual (May 2014)

Short Table of Contents

Table of Contents

LaTeX2e

This document is an unofficial reference manual for LaTeX, a document preparation system, version as of May 2014. It is intended to cover LaTeX2e, which has been the standard version of LaTeX for many years.

1 About this document

The LaTeX document preparation system is implemented as a macro package for Donald E. Knuth’s TeX typesetting program. LaTeX was originally created by Leslie Lamport; it is now maintained by a group of volunteers (http://latex-project.org). The official documentation written by the LaTeX project is available from their web site.

The present 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.

The home page for this document is http://home.gna.org/latexrefman. That page has links to the current output in various formats, sources, mailing lists, and other infrastructure.

Of course, there are many, many other sources of information about LaTeX. Here are a few:

http://www.ctan.org/pkg/latex-doc-ptr

Two pages of recommended references to LaTeX documentation.

http://www.ctan.org/pkg/first-latex-doc

Writing your first document, with a bit of both text and math.

http://www.ctan.org/pkg/usrguide

The guide for document authors maintained as part of LaTeX; there are several others.

http://tug.org/begin.html

Introduction to the TeX system, including LaTeX.

2 Overview of LaTeX

What is LaTeX?

LaTeX typesets a file of text using the TeX program and the LaTeX “macro package” for TeX. That is, it processes an input file containing the text of a document with interspersed commands that describe how the text should be formatted. LaTeX files are plain text that can be written in any reasonable editor. It produces at least three files as output:

1. The main output file, which is one of:

   .dvi

   If invoked as latex, a “Device Independent” (.dvi) file is produced. This contains commands that can be translated into commands for virtually any output device. You can view such .dvi output of LaTeX by using a program such as xdvi (display directly), dvips (convert to PostScript), or dvipdfmx (convert to PDF).

   .pdf

   If invoked as pdflatex, a “Portable Document Format” (.pdf) file. Typically, this is a self-contained file, with all fonts and images embedded. This can be very useful, but it does make the output much larger than the .dvi produced from the same document.

   If invoked as lualatex, a .pdf file is created using the LuaTeX engine (http://luatex.org).

   If invoked as xelatex, a .pdf file is created using the XeTeX engine (http://tug.org/xetex).

   Many other less-common variants of LaTeX (and TeX) exist, which can produce HTML, XML, and other things.

2. The “transcript” or .log file that contains summary information and diagnostic messages for any errors discovered in the input file.
3. An “auxiliary” or .aux file. This is used by LaTeX itself, for things such as cross-references.

An open-ended list of other files might be created. We won’t try to list them all. Xxx components?

In the LaTeX input file, a command name starts with a \, followed by either (a) a string of letters or (b) a single non-letter. Arguments contained in square brackets, [], are optional while arguments contained in braces, {}, are required.

LaTeX is case sensitive. Enter all commands in lower case unless explicitly directed to do otherwise.

3 Starting & ending

A minimal input file looks like the following:

\documentclass{class}
\begin{document}
your text
\end{document}

where the class is a valid document class for LaTeX. See Document classes, for details of the various document classes available locally.

You may include other LaTeX commands between the \documentclass and the \begin{document} commands (this area is called the preamble).

4 Document classes

The class of a given document is defined with the command:

\documentclass[options]{class}

The \documentclass command must be the first command in a LaTeX source file.

Built-in LaTeX document class names are (many other document classes are available as add-ons; see Overview):

article  report  book  letter  slides

Standard options are described below.

4.1 Document class options

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

\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 (default is letterpaper):

a4paper a5paper b5paper executivepaper legalpaper letterpaper

Miscellaneous other options:

draft, final

mark/do not mark overfull boxes with a big black box; 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.

These 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 for the book class.

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. The defaults vary with the paper size and whether one- or two-side layout is selected. For one-sided printing the text is centered, for two-sided, \oddsidemargin is 40% of the difference between \paperwidth and \textwidth, with \evensidemargin the remainder.

openright

openany

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

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 pkg, you can separate them with a comma, 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.

5 Fonts

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

5.1 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{italic text}. In the table below, the corresponding command in parenthesis is the “declaration form”, which takes no arguments. 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 commands automatically supply an italic correction if needed.

\textrm (\rmfamily)

Roman.

\textit (\itshape)

Italics.

\emph

Emphasis (switches between \textit and \textrm).

\textmd (\mdseries)

Medium weight (default).

\textbf (\bfseries)

Boldface.

\textup (\upshape)

Upright (default). The opposite of slanted.

\textsl (\slshape)

Slanted.

\textsf (\sffamily)

Sans serif.

\textsc (\scshape)

Small caps.

\texttt (\ttfamily)

Typewriter.

\textnormal (\normalfont)

Main document font.

\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. 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.

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 very different things.

\bf

Switch to bold face.

\cal

Switch to calligraphic letters for math.

\em

Emphasis (italics within roman, roman within italics).

\it

Italics.

\rm

Roman.

\sc

Small caps.

\sf

Sans serif.

\sl

Slanted (oblique).

\tt

Typewriter (monospace, fixed-width).

Some people consider the unconditional font-switching commands, such as \tt, obsolete and only the cumulative commands (\texttt) should be used. I (Karl) do not agree. There are perfectly reasonable situations when an unconditional font switch is precisely what you need to get the desired output; for one example, see description. Both sets of commands have their place.

5.2 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).

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}.

5.3 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{enc}

Select font encoding. Valid encodings include OT1 and T1.

\fontfamily{family}

Select font family. Valid families include:

• cmr for Computer Modern Roman
• cmss for Computer Modern Sans Serif
• cmtt for Computer Modern Typewriter

and numerous others.

\fontseries{series}

Select font series. Valid series include:

• m Medium (normal)
• b Bold
• c Condensed
• bc Bold condensed
• bx Bold extended

and various other combinations.

\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.

\fontsize{size}{skip}

Set font size. The first parameter is the font size to switch to and the second is the line spacing to use; this is stored in a parameter named \baselineskip. The unit of both parameters defaults to pt. The default \baselineskip for the Computer Modern typeface is 1.2 times the \fontsize.

The line spacing is also multiplied by the value of the \baselinestretch parameter when the type size changes; the default is 1. However, the best way to “double space” a document, if you should be unlucky enough to have to produce such, is to use the setspace package; see http://www.tex.ac.uk/cgi-bin/texfaq2html?label=linespace.

\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 described just above.

The changes made by calling the font commands described above do not come into effect until \selectfont is called.

\usefont{enc}{family}{series}{shape}

The same as invoking \fontencoding, \fontfamily, \fontseries and \fontshape with the given parameters, followed by \selectfont.

6 Layout

Miscellaneous commands for controlling the general layout of the page.

6.1 \onecolumn

The \onecolumn declaration starts a new page and produces single-column output. This is the default.

6.2 \twocolumn

Synopsis:

\twocolumn[text1col]

The \twocolumn declaration starts a new page and produces two-column output. If the optional text1col argument is present, it is typeset in one-column mode before the two-column typesetting starts.

These parameters control typesetting in two-column output:

\columnsep

The distance between columns (35pt by default).

\columnseprule

The width of the rule between columns; the default is 0pt, so there is no rule.

\columnwidth

The width of the current column; this is equal to \textwidth in single-column text.

These parameters control float behavior in two-column output:

\dbltopfraction

Maximum fraction at the top of a two-column page that may be occupied by floats. Default ‘.7’, can be usefully redefined to (say) ‘.9’ to avoid going to float pages so soon.

\dblfloatpagefraction

The minimum fraction of a float page that must be occupied by floats, for a two-column float page. Default ‘.5’.

\dblfloatsep

Distance between floats at the top or bottom of a two-column float page. Default ‘12pt plus2pt minus2pt’ for ‘10pt’ and ‘11pt’ documents, ‘14pt plus2pt minus4pt’ for ‘12pt’.

\dbltextfloatsep

Distance between a multi-column float at the top or bottom of a page and the main text. Default ‘20pt plus2pt minus4pt’.

6.3 \flushbottom

The \flushbottom declaration makes all text pages the same height, adding extra vertical space where necessary to fill out the page.

This is the default if twocolumn mode is selected (see Document class options).

6.4 \raggedbottom

The \raggedbottom declaration makes all pages the natural height of the material on that page. No rubber lengths will be stretched.

6.5 Page layout parameters

\headheight

Height of the box that contains the running head. Default is ‘30pt’, except in the book class, where it varies with the type size.

\headsep

Vertical distance between the bottom of the header line and the top of the main text. Default is ‘25pt’, except in the book class, where it varies with the type size.

\footskip

Distance from the baseline of the last line of text to the baseline of the page footer. Default is ‘30pt’, except in the book class, where it varies with the type size.

\linewidth

Width of the current line, decreased for each nested list (see list). Specifically, it is smaller than \textwidth by the sum of \leftmargin and \rightmargin (see itemize). The default varies with the font size, paper width, two-column mode, etc. For an article document in ‘10pt’, it’s set to ‘345pt’; in two-column mode, that becomes ‘229.5pt’.

\textheight

The normal vertical height of the page body; the default varies with the font size, document class, etc. For an article or report document in ‘10pt’, it’s set to ‘43\baselineskip’; for book, it’s ‘41\baselineskip’. For ‘11pt’, it’s ‘38\baselineskip’ and for ‘12pt’, ‘36\baselineskip’.

\textwidth

The full horizontal width of the entire page body; the default varies as usual. For an article or report document, it’s ‘345pt’ at ‘10pt’, ‘360pt’ at ‘11pt’, and ‘390pt’ at ‘12pt’. For a book document, it’s ‘4.5in’ at ‘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.

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 default 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 clases, the default is the same as the font size, e.g., ‘10pt’ at ‘10pt’.

7 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.)

8 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.”

8.1 \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.

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

To avoid accidentally creating two labels with the same name, it is common to use labels consisting of a prefix and a suffix separated by a colon or period. Some conventionally-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:snark or fig.snark.

8.2 \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.

8.3 \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.

9 Environments

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

\begin{envname}
...
\end{envname}

9.1 abstract

Synopsis:

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

Environment for producing an abstract, possibly of multiple paragraphs.

9.2 array

Synopsis:

\begin{array}{template}
col1 text&col1 text&coln}\\
...
\end{array}

Math arrays are produced with the array environment, normally within an equation environment (see equation). It has a single mandatory template argument describing the number of columns and the alignment within them. Each column col is specified by a single letter that tells how items in that row should be formatted, as follows:

c

centered

l

flush left

r

flush right

Column entries are separated by &. Column entries may include other LaTeX commands. Each row of the array is terminated with \\.

In the template, the construct @{text} puts text between columns in each row.

Here’s an example:

\begin{equation}
  \begin{array}{lrc}
  left1 & right1 & centered1 \\
  left2 & right2 & centered2 \\
  \end{array}
\end{equation}

The \arraycolsep parameter defines half the width of the space separating columns; the default is ‘5pt’. See tabular, for other parameters which affect formatting in array environments, namely \arrayrulewidth and \arraystretch.

The array environment can only be used in math mode.

9.3 center

Synopsis:

\begin{center}
line1 \\
line2 \\
\end{center}

The center environment allows you to create a paragraph consisting of lines that are centered within the left and right margins on the current page. Each line is terminated with the string \\.

9.3.1 \centering

The \centering declaration corresponds to the center environment. This declaration can be used inside an environment such as quote or in a parbox. Thus, the text of a figure or table can be centered on the page by putting a \centering command at the beginning of the figure or table environment.

Unlike the center environment, the \centering command does not start a new paragraph; it simply 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 (of an environment such as quote) that ends the paragraph unit.

Here’s an example:

\begin{quote}
\centering
first line \\
second line \\
\end{quote}

9.4 description

Synopsis:

\begin{description}
\item [label1] item1
\item [label2] item2
...
\end{description}

The description environment is used to make labelled lists. Each label is typeset in bold, flush right. The item text may contain multiple paragraphs.

Another variation: since the bold style is applied to the labels, if you typeset a label in typewriter using \texttt, you’ll get bold typewriter: \item[\texttt{bold and typewriter}]. This may be too bold, among other issues. To get just typewriter, use \tt, which resets all other style variations: \item[{\tt plain typewriter}].

For details about list spacing, see itemize.

9.5 displaymath

Synopsis:

\begin{displaymath}
math
\end{displaymath}

or

\[math\]

The displaymath environment (\[...\] is a synonym) typesets the math text on its own line, centered by default. The global fleqn option makes equations flush left; see Document class options.

No equation number is added to displaymath text; to get an equation number, use the equation environment (see equation).

9.6 document

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

9.7 enumerate

Synopsis:

\begin{enumerate}
\item item1
\item item2
...
\end{enumerate}

The enumerate environment produces a numbered list. Enumerations can be nested within one another, up to four levels deep. They can also be nested within other paragraph-making environments, such as itemize (see itemize) and description (see description).

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

By default, the numbering at each level is done like this:

1. 1., 2., …
2. (a), (b), …
3. i., ii., …
4. A., B., …

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

The enumerate environment uses the commands \labelenumi through \labelenumiv to produce the default label. So, you can use \renewcommand to change the labels (see \newcommand & \renewcommand). For instance, to have the first level use uppercase letters:

\renewcommand{\labelenumi}{\Alph{enumi}}

9.8 eqnarray

First, a caveat: the eqnarray environment has some infelicities which cannot be overcome; the article “Avoid eqnarray!” by Lars Madsen describes them in detail (http://tug.org/TUGboat/tb33-1/tb103madsen.pdf). The bottom line is that it is better to use the align environment (and others) from the amsmath package.

Nevertheless, here is a description of eqnarray:

\begin{eqnarray}  (or eqnarray*)
formula1 \\
formula2 \\
...
\end{eqnarray}

The eqnarray environment is used to display a sequence of equations or inequalities. It is very much like a three-column array environment, with consecutive rows separated by \\ and consecutive items within a row separated by an &.

\\* can also be used to separate equations, with its normal meaning of not allowing a page break at that line.

An equation number is placed on every line unless that line has a \nonumber command. Alternatively, The *-form of the environment (\begin{eqnarray*} ... \end{eqnarray*}) will omit equation numbering entirely, while otherwise being the same as eqnarray.

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.

9.9 equation

Synopsis:

\begin{equation}
math
\end{equation}

The equation environment starts a displaymath environment (see displaymath), e.g., centering the math text on the page, and also places an equation number in the right margin.

9.10 figure

\begin{figure[*]}[placement]
figbody
\label{label}
\caption[loftitle]{text}
\end{figure}

Figures are objects that are not part of the normal text, and are instead “floated” to a convenient place, such as the top of a page. Figures will not be split between two pages.

When typesetting in double-columns, the starred form produces a full-width figure (across both columns).

The optional argument [placement] determines where LaTeX will try to place your figure. There are four places where LaTeX can possibly put a float:

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, this is not allowed by itself; t is automatically added.

To absolutely force a figure 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.

The standard report and article classes use the default placement tbp.

The body of the figure is made up of whatever text, LaTeX commands, etc. you wish.

The \caption command specifies caption text for the figure. The caption is numbered by default. If loftitle is present, it is used in the list of figures instead of text (see Tables of contents).

Parameters relating to fractions of pages occupied by float and non-float text:

The maximum fraction of the page allowed to be occuped 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:

\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 ‘10pt’ and ‘11pt’ styles, ‘14pt plus4pt minus4pt’ for ‘12pt’.

\textfloatsep

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

Parameters relating to the number of floats on a page:

\bottomnumber

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

\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.

9.11 filecontents: Create external files

Synopsis:

\begin{filecontents}{filename}
contents-of-file
\end{filecontents}
...
\documentclass{my-document-class}

The filecontents environment is an initial command, meaning that it can be used only before the \documentclass command, as in the synopsis above.

LaTeX will create a file named filename with the content contents-of-file preceded by a header comment indicating how and when the file was generated. If the file already exists then nothing will happen.

You can also use the filecontents package, which has the following advantages:

• If the file already exists, then it will be overwritten.
• You can use the filecontents environment at any point after the declaration \usepackage{filecontents}, not just before \documentclass.
• The filecontents package also provides a filecontents* environment which is used in the same way as the filecontents environment except that it won’t insert any leading comment, so it is better suited to create files which aren’t in LaTeX format.

The filecontents environment only creates the file, and is unrelated to using the created file. So you need to use, for instance, \input or \usepackage or \bibliography or whatever is applicable, to use the created file.

This environment is also useful to make a self-contained document, for example, for a bug report, or to keep a .bib file with the main document.

9.12 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 \\.

9.12.1 \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.

9.13 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 string \\.

9.13.1 \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.

9.14 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}}

9.15 letter environment: writing letters

This environment is used for creating letters. See Letters.

9.16 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).

9.17 math

Synopsis:

\begin{math}
math
\end{math}

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

9.18 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.

9.19 picture

\begin{picture}(width,height)(x offset,y offset)
… 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. It specifies the size of the picture. The environment produces a rectangular box with width and height determined by this argument’s x- and y-coordinates.

The picture environment also has an optional position argument, 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.

9.19.1 \circle

\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 40 pt can be drawn.

9.19.2 \makebox

\makebox(width,height)[position]{...}

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.

9.19.3 \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.

9.19.4 \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.

9.19.5 \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.

9.19.6 \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, not to mention other shapes, see the curve2e and many many other packages on CTAN.

9.19.7 \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.

9.19.8 \thicklines

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

9.19.9 \thinlines

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

9.19.10 \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.

9.19.11 \oval

Synopsis:

\oval(width,height)[portion]

The \oval command produces a rectangle with rounded corners. The optional argument portion allows you to select part of the oval via the following:

t

selects the top portion;

b

selects the bottom portion;

r

selects the right portion;

l

selects the left portion.

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.

9.19.12 \put

\put(x coord,y coord){ ... }

The \put command places the item specified by the mandatory argument at the given coordinates.

9.19.13 \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 \\.

9.19.14 \vector

Synopsis:

\vector(x-slope,y-slope){length}

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

9.20 quotation

Synopsis:

\begin{quotation}
text
\end{quotation}

The margins of the quotation environment are indented on both the left and the right. The text is justified at both margins. Leaving a blank line between text produces a new paragraph.

Unlike the quote environment, each paragraph is indented normally.

9.21 quote

Snyopsis:

\begin{quote}
text
\end{quote}

The margins of the quote environment are indented on both the left and the right. The text is justified at both margins. Leaving a blank line between text produces a new paragraph.

Unlike the quotation environment, paragraphs are not indented.

9.22 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 enviroment:

\\ (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}

9.23 table

Synopsis:

 \begin{table}[placement]

  body of the table

 \caption{table title}
 \end{table}

Tables are objects that are not part of the normal text, and are usually “floated” to a convenient place, like the top of a page. Tables will not be split between two pages.

The optional argument [placement] determines where LaTeX will try to place your table. There are four places where LaTeX can possibly put a float; these are the same as that used with the figure environment, and described there (see figure).

The standard report and article classes use the default placement [tbp].

The body of the table is made up of whatever text, LaTeX commands, etc., you wish. The \caption command allows you to title your table.

9.24 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 box consisting of a sequence of rows of items, aligned vertically in columns.

\\ must be used to specify the end of each row of the table, except for the last, where it is optional—unless an \hline command (to put a rule below the table) follows.

The mandatory and optional arguments consist of:

width

Specifies the width of the tabular* environment. There must be rubber space between columns that can stretch to fill out the specified width.

pos

Specifies the vertical position; default is alignment on the centre of the environment.

t

align on top row

b

align on bottom row

cols

Specifies the column formatting. It consists of a sequence of the following specifiers, corresponding to the sequence of columns 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}

This inserts text in every row. An @-expression suppresses the intercolumn space normally inserted between columns; any desired space before the adjacent item must be included in text.

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

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.

p{wd}

Produces a column with each item typeset in a parbox of width wd, as if it were the argument of a \parbox[t]{wd} command. However, a \\ may not appear in the item, except in the following situations:

1. inside an environment like minipage, array, or tabular.
2. inside an explicit \parbox.
3. in the scope of a \centering, \raggedright, or \raggedleft declaration. The latter declarations must appear inside braces or an environment when used in a p-column element.

*{num}{cols}

Equivalent to num copies of cols, where num is a positive integer and cols is any list of column-specifiers, which may contain another *-expression.

Parameters that control formatting:

\arrayrulewidth

Thickness of the rule created by |, \hline, and \vline in the tabular and array environments; the default is ‘.4pt’.

\arraystretch

Scaling of spacing between rows in the tabular and array environments; default is ‘1’, for no scaling.

\doublerulesep

Horizontal distance between the vertical rules produced by || in the tabular and array environments; default is ‘2pt’.

\tabcolsep

Half the width of the space between columns; default is ‘6pt’.

The following commands can be used inside a tabular environment:

9.24.1 \multicolumn

Synopsis:

\multicolumn{cols}{pos}{text}

The \multicolumn command makes an entry that spans several columns. The first mandatory argument, cols, specifies the number of columns to span. The second mandatory argument, pos, specifies the formatting of the entry; c for centered, l for flushleft, r for flushright. The third mandatory argument, text, specifies what text to put in the entry.

Here’s an example showing two columns separated by an en-dash; \multicolumn is used for the heading:

\begin{tabular}{r@{--}l}
\multicolumn{2}{c}{\bf Unicode}\cr
   0x80&0x7FF   \cr
  0x800&0xFFFF  \cr
0x10000&0x1FFFF \cr
\end{tabular}

9.24.2 \cline

Synopsis:

\cline{i-j}

The \cline command draws horizontal lines across the columns specified, beginning in column i and ending in column j, which are specified in the mandatory argument.

9.24.3 \hline

The \hline command 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.

9.24.4 \vline

The \vline command will draw a vertical line extending the full height and depth of its row. An \hfill command can be used to move the line to the edge of the column. It can also be used in an @-expression.

9.25 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.

9.25.1 \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.

9.25.2 \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]’.

9.25.3 \nocite

\nocite{key_list}

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

9.25.4 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://www.ctan.org/tex-archive/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.

9.26 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).

9.27 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.

9.28 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).

9.28.1 \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.

9.29 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.

10 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 for you, but in some environments, you do the line breaking yourself with the \\ command, and you can always manually force breaks.

10.1 \\[*][morespace]

The \\ command tells LaTeX to start a new line. It has an optional argument, morespace, that specifies how much extra vertical space is to be inserted before the next line. This can be a negative amount.

The \\* command is the same as the ordinary \\ command except that it tells LaTeX not to start a new page after the line.

10.2 \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.

10.3 \newline

The \newline command breaks the line at the present point, with no stretching of the text before it. It can only be used in paragraph mode.

10.4 \- (discretionary hyphen)

The \- command tells LaTeX that it may hyphenate the word at that point. LaTeX is very good at hyphenating, and it will usually find most of the correct hyphenation points, and almost never use 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.

10.5 \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.

10.6 \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).

10.7 \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}

10.8 \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.

11 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.

11.1 \cleardoublepage

The \cleardoublepage command ends the current page and causes all 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.

11.2 \clearpage

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

11.3 \newpage

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

11.4 \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.

11.5 \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.

12 Footnotes

Footnotes can be produced in one of two ways. They can be produced with one command, the \footnote command. They can also be produced with two commands, the \footnotemark and the \footnotetext commands.

12.1 \footnote

Synopsis:

\footnote[number]{text}

The \footnote command places the numbered footnote text at the bottom of the current page. The optional argument number changes the default footnote number.

This command can only be used in outer paragraph mode; i.e., you cannot use it in sectioning commands like \chapter, in figures, tables or in a tabular environment. (See following sections.)

12.2 \footnotemark

With no optional argument, the \footnotemark command puts the current footnote number in the text. This command can be used in inner paragraph mode. You give the text of the footnote separately, with the \footnotetext command.

This command can be used to produce several consecutive footnote markers referring to the same footnote with

\footnotemark[\value{footnote}]

after the first \footnote command.

12.3 \footnotetext

Synopsis:

\footnotetext[number]{text}

The \footnotetext command places text at the bottom of the page as a footnote. This command can come anywhere after the \footnotemark command. The \footnotetext command must appear in outer paragraph mode.

The optional argument number changes the default footnote number.

12.4 Symbolic footnotes

If you want to use symbols for footnotes, rather than increasing numbers, redefine \thefootnote like this:

\renewcommand{\thefootnote}{\fnsymbol{footnote}}

The \fnsymbol command produces a predefined series of symbols (see \alph \Alph \arabic \roman \Roman \fnsymbol). If you want to use a different symbol as your footnote mark, you’ll need to also redefine \@fnsymbol.

12.5 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’.

13 Definitions

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

13.1 \newcommand & \renewcommand

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

  \newcommand[*]{cmd}[nargs][optarg]{defn}
\renewcommand[*]{cmd}[nargs][optarg]{defn}

*

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

cmd

The command name beginning with \. For \newcommand, it must not be already defined and must not begin with \end; for \renewcommand, it must already be defined.

nargs

An optional integer from 1 to 9 specifying the number of arguments that the command will take. The default is for the command to have no arguments.

optarg

If this optional parameter is present, it means that the command’s first argument is optional. The default value of the optional argument (i.e., if it is not specified in the call) is optarg, or, if that argument is present in the \newcommand but has an empty value, the string ‘def’.

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.

13.2 \newcounter

Synopsis:

\newcounter{cnt}[countername]

The \newcounter command defines a new counter named cnt. The new counter is initialized to zero.

Given the optional argument [countername], cnt will be reset whenever countername is incremented.

See Counters, for more information about counters.

13.3 \newlength

Synopsis:

\newlength{\arg}

The \newlength command defines the mandatory argument as a length command with a value of 0in. The argument must be a control sequence, as in \newlength{\foo}. An error occurs if \foo is already defined.

See Lengths, for how to set the new length to a nonzero value, and for more information about lengths in general.

13.4 \newsavebox

Synopsis:

\newsavebox{cmd}

Defines \cmd, which must be a command name not already defined, to refer to a new bin for storing boxes.

13.5 \newenvironment & \renewenvironment

Synopses:

  \newenvironment[*]{env}[nargs][default]{begdef}{enddef}
\renewenvironment[*]{env}[nargs]{begdef}{enddef}

These commands define or redefine an environment env, that is, \begin{env} … \end{env}.

*

The *-form of these commands requires that the arguments (not the contents of the environment) not contain multiple paragraphs of text.

env

The name of the environment. For \newenvironment, env must not be an existing environment, and the command \env must be undefined. For \renewenvironment, env must be the name of an existing environment.

nargs

An integer from 1 to 9 denoting the number of arguments of the newly-defined environment. The default is no arguments.

default

If this is specified, the first argument is optional, and default gives the default value for that argument.

begdef

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.

enddef

The text expanded at every occurrence of \end{env}. It may not contain any argument parameters.

13.6 \newtheorem

\newtheorem{newenv}{label}[within]
\newtheorem{newenv}[numbered_like]{label}

This command defines a theorem-like environment. Arguments:

newenv

The name of the environment to be defined; must not be the name of an existing environment or otherwise defined.

label

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

numbered_like

(Optional.) The name of an already defined theorem-like environment; the new environment will be numbered just like numbered_like.

within

(Optional.) The name of an already defined counter, a sectional unit. The new theorem counter will be reset at the same time as the within counter.

At most one of numbered_like and within can be specified, not both.

13.7 \newfont

Synopsis:

\newfont{cmd}{fontname}

Defines a control sequence \cmd, which must not already be defined, to make fontname be the current font. The file looked for on the system is named fontname.tfm.

This is a low-level command for setting up to use an individual font. More commonly, fonts are defined in families through .fd files.

13.8 \protect

Footnotes, line breaks, any command that has an optional argument, and many more are so-called fragile commands. When a fragile command is used in certain contexts, called moving arguments, it must be preceded by \protect. In addition, any fragile commands within the arguments must have their own \protect.

Some examples of moving arguments are \caption (see figure), \thanks (see \maketitle), and expressions in tabular and array environments (see tabular).

Commands which are not fragile are called robust. They must not be preceded by \protect.

See also:

http://www-h.eng.cam.ac.uk/help/tpl/textprocessing/teTeX/latex/latex2e-html/fragile.html

http://www.tex.ac.uk/cgi-bin/texfaq2html?label=protect

14 Counters

Everything LaTeX numbers for you has a counter associated with it. The name of the counter is the same as the name of the environment or command that produces the number, except with no \. (enumi–enumiv are used for the nested enumerate environment.) 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

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

All of these commands take a single counter as an argument, for instance, \alph{enumi}.

\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.

The symbols mostly aren’t supported in Info, but here are the names:

asterisk(*) dagger ddagger section-sign paragraph-sign parallel
double-asterisk(**) double-dagger double-ddagger

14.2 \usecounter{counter}

Synopsis:

\usecounter{counter}

The \usecounter command is used in the second argument of the list environment to specify counter to be used to number the list items.

14.3 \value{counter}

Synopsis:

\value{counter}

The \value command produces the value of counter. It can be used anywhere LaTeX expects a number, for example:

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

14.4 \setcounter{counter}{value}

Synopsis:

\setcounter{\counter}{value}

The \setcounter command sets the value of \counter to the value argument.

14.5 \addtocounter{counter}{value}

The \addtocounter command increments counter by the amount specified by the value argument, which may be negative.

14.6 \refstepcounter{counter}

The \refstepcounter command works in the same way as \stepcounter See \stepcounter, except it also defines the current \ref value to be the result of \thecounter.

14.7 \stepcounter{counter}

The \stepcounter command adds one to counter and resets all subsidiary counters.

14.8 \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).

15 Lengths

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

15.1 \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.

15.2 \addtolength{\len}{amount}

The \addtolength command increments a “length command” \len by the amount specified in the amount argument, which may be negative.

15.3 \settodepth

\settodepth{\gnat}{text}

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

15.4 \settoheight

\settoheight{\gnat}{text}

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

15.5 \settowidth{\len}{text}

The \settowidth command sets the value of the command \len to the width of the text argument.

15.6 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}

16 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.

16.1 \indent

\indent produces a horizontal space whose width equals the width of 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.

16.2 \noindent

When used at the beginning of the paragraph, \noindent suppresses any paragraph indentation. It has no effect when used in the middle of a paragraph.

16.3 \parskip

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

16.4 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;
• in the outside margin for two-sided layout;
• in the nearest margin for two-column layout.

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.

17 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 $

17.1 Subscripts & superscripts

To get an expression exp to appear as a subscript, you just type _{exp}. To get exp to appear as a superscript, you type ^{exp}. LaTeX handles superscripted superscripts and all of that stuff in the natural way. It even does the right thing when something has both a subscript and a superscript.

17.2 Math symbols

LaTeX provides almost any mathematical symbol you’re likely to need. The commands for generating them can be used only in math mode. For example, if you include $\pi$ in your source, you will get the pi symbol (\pi) in your output.

\|

\|

\aleph

\aleph

\alpha

\alpha

\amalg

\amalg (binary operation)

\angle

\angle

\approx

\approx (relation)

\ast

\ast (binary operation)

\asymp

\asymp (relation)

\backslash

\ (delimiter)

\beta

\beta

\bigcap

\bigcap

\bigcirc

\bigcirc (binary operation)

\bigcup

\bigcup

\bigodot

\bigodot

\bigoplus

\bigoplus

\bigotimes

\bigotimes

\bigtriangledown

\bigtriangledown (binary operation)

\bigtriangleup

\bigtriangleup (binary operation)

\bigsqcup

\bigsqcup

\biguplus

\biguplus

\bigcap

\bigvee

\bigwedge

\bigwedge

\bot

\bot

\bowtie

\bowtie (relation)

\Box

(square open box symbol)

\bullet

\bullet (binary operation)

\cap

\cap (binary operation)

\cdot

\cdot (binary operation)

\chi

\chi

\circ

\circ (binary operation)

\clubsuit

\clubsuit

\cong

\cong (relation)

\coprod

\coprod

\cup

\cup (binary operation)

\dagger

\dagger (binary operation)

\dashv

\dashv (relation)

\ddagger

\dagger (binary operation)

\Delta

\Delta

\delta

\delta

\Diamond

bigger \diamond

\diamond

\diamond (binary operation)

\diamondsuit

\diamondsuit

\div

\div (binary operation)

\doteq

\doteq (relation)

\downarrow

\downarrow (delimiter)

\Downarrow

\Downarrow (delimiter)

\ell

\ell

\emptyset

\emptyset

\epsilon

\epsilon

\equiv

\equiv (relation)

\eta

\eta

\exists

\exists

\flat

\flat

\forall

\forall

\frown

\frown (relation)

\Gamma

\Gamma

\gamma

\gamma

\ge

\ge

\geq

\geq (relation)

\gets

\gets

\gg

\gg (relation)

\hbar

\hbar

\heartsuit

\heartsuit

\hookleftarrow

\hookleftarrow

\hookrightarrow

\hookrightarrow

\iff

\iff

\Im

\Im

\in

\in (relation)

\infty

\infty

\int

\int

\iota

\iota

\Join

condensed bowtie symbol (relation)

\kappa

\kappa

\Lambda

\Lambda

\lambda

\lambda

\land

\land

\langle

\langle (delimiter)

\lbrace

\lbrace (delimiter)

\lbrack

\lbrack (delimiter)

\lceil

\lceil (delimiter)

\le

\le

\leadsto

\Leftarrow

\Leftarrow

\leftarrow

\leftarrow

\leftharpoondown

\leftharpoondown

\leftharpoonup

\leftharpoonup

\Leftrightarrow

\Leftrightarrow

\leftrightarrow

\leftrightarrow

\leq

\leq (relation)

\lfloor

\lfloor (delimiter)

\lhd

(left-pointing arrow head)

\ll

\ll (relation)

\lnot

\lnot

\longleftarrow

\longleftarrow

\longleftrightarrow

\longleftrightarrow

\longmapsto

\longmapsto

\longrightarrow

\longrightarrow

\lor

\lor

\mapsto

\mapsto

\mho

\mid

\mid (relation)

\models

\models (relation)

\mp

\mp (binary operation)

\mu

\mu

\nabla

\nabla

\natural

\natural

\ne

\ne

\nearrow

\nearrow

\neg

\neg

\neq

\neq (relation)

\ni

\ni (relation)

\not

Overstrike a following operator with a /, as in \not=.

\notin

\ni

\nu

\nu

\nwarrow

\nwarrow

\odot

\odot (binary operation)

\oint

\oint

\Omega

\Omega

\omega

\omega

\ominus

\ominus (binary operation)

\oplus

\oplus (binary operation)

\oslash

\oslash (binary operation)

\otimes

\otimes (binary operation)

\owns

\owns

\parallel

\parallel (relation)

\partial

\partial

\perp

\perp (relation)

\phi

\phi

\Pi

\Pi

\pi

\pi

\pm

\pm (binary operation)

\prec

\prec (relation)

\preceq

\preceq (relation)

\prime

\prime

\prod

\prod

\propto

\propto (relation)

\Psi

\Psi

\psi

\psi

\rangle

\rangle (delimiter)

\rbrace

\rbrace (delimiter)

\rbrack

\rbrack (delimiter)

\rceil

\rceil (delimiter)

\Re

\Re

\rfloor

\rfloor

\rhd

(binary operation)

\rho

\rho

\Rightarrow

\Rightarrow

\rightarrow

\rightarrow

\rightharpoondown

\rightharpoondown

\rightharpoonup

\rightharpoonup

\rightleftharpoons

\rightleftharpoons

\searrow

\searrow

\setminus

\setminus (binary operation)

\sharp

\sharp

\Sigma

\Sigma

\sigma

\sigma

\sim

\sim (relation)

\simeq

\simeq (relation)

\smallint

\smallint

\smile

\smile (relation)

\spadesuit

\spadesuit

\sqcap

\sqcap (binary operation)

\sqcup

\sqcup (binary operation)

\sqsubset

(relation)

\sqsubseteq

\sqsubseteq (relation)

\sqsupset

(relation)

\sqsupseteq

\sqsupseteq (relation)

\star

\star (binary operation)

\subset

\subset (relation)

\subseteq

\subseteq (relation)

\succ

\succ (relation)

\succeq

\succeq (relation)

\sum

\sum

\supset

\supset (relation)

\supseteq

\supseteq (relation)

\surd

\surd

\swarrow

\swarrow

\tau

\tau

\theta

\theta

\times

\times (binary operation)

\to

\to

\top

\top

\triangle

\triangle

\triangleleft

\triangleleft (binary operation)

\triangleright

\triangleright (binary operation)

\unlhd

left-pointing arrowhead with line under (binary operation)

\unrhd

right-pointing arrowhead with line under (binary operation)

\Uparrow

\Uparrow (delimiter)

\uparrow

\uparrow (delimiter)

\Updownarrow

\Updownarrow (delimiter)

\updownarrow

\updownarrow (delimiter)

\uplus

\uplus (binary operation)

\Upsilon

\Upsilon

\upsilon

\upsilon

\varepsilon

\varepsilon

\varphi

\varphi

\varpi

\varpi

\varrho

\varrho

\varsigma

\varsigma

\vartheta

\vartheta

\vdash

\vdash (relation)

\vee

\vee (binary operation)

\Vert

\Vert (delimiter)

\vert

\vert (delimiter)

\wedge

\wedge (binary operation)

\wp

\wp

\wr

\wr (binary operation)

\Xi

\Xi

\xi

\xi

\zeta

\zeta

17.3 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

\cos

\coth

\cosh

\csc

\csc

\deg

\deg

\det

\deg

\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

17.4 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: \acute{x}.

\bar

Math bar-over accent: \bar{x}.

\breve

Math breve accent: \breve{x}.

\check

Math háček (check) accent: \check{x}.

\ddot

Math dieresis accent: \ddot{x}.

\dot

Math dot accent: \dot{x}.

\grave

Math grave accent: \grave{x}.

\hat

Math hat (circumflex) accent: \hat{x}.

\imath

Math dotless i.

\jmath

Math dotless j.

\mathring

Math ring accent: x*.

\tilde

Math tilde accent: \tilde{x}.

\vec

Math vector symbol: \vec{x}.

\widehat

Math wide hat accent: \widehat{x+y}.

\widehat

Math wide tilde accent: \widetilde{x+y}.

17.5 Spacing in math mode

In a math environment, LaTeX ignores the spaces you type and puts in the spacing according to the normal rules for mathematics texts. If you want different spacing, LaTeX provides the following commands for use in math mode:

\;

A thick space (5\over18\,quad).

\:

\>

Both of these produce a medium space (2\over9\,quad).

\,

A thin space (1\over6\,quad); not restricted to math mode.

\!

A negative thin space (-{1\over6}\,quad).

17.6 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, \overbrace{x+\cdots+x}^{k \rm\;times}.

\overline{text}

Generates a horizontal line over tex. For exampe, \overline{x+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.

18 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

LaTeX changes mode only when it goes up or down a staircase to a different level, though not all level changes produce mode changes. 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 that mode, LaTeX breaks your text into lines and breaks the lines into pages. LaTeX is in “math mode” when it’s generating a mathematical formula. 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 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 in paragraph mode. The box make 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”. Its normal paragraph mode, which it starts out in, is called “outer paragraph mode”.

19 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.

19.1 \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.