Marco Colombo

Structure of an empty latex file

\documentclass[11pt,a4paper]{article}

\begin{document}
  %
  % [...]
  %
\end{document}

Include a file when a large document is split into different files

\include{filename}

Change the margins

\addtolength{\textheight}{2.4cm}
\addtolength{\hoffset}{-1.2cm}
\addtolength{\voffset}{-2cm}
\addtolength{\textwidth}{2.3cm}

These are the margins I use more often, as the page becomes larger but not too crammed.

Tell latex that the document is in a draft state

\documentclass[draft]{article}

Latex will print a black square beside the lines that are too long.

Print 'Draft' across all pages of the document in a light grey colour

\usepackage[light,all]{draftcopy}

Doublespace the text

\usepackage{setspace} 
\doublespacing

One-and-half spacing

\usepackage{setspace} 
\onehalfspacing

Change the simbol of the second level of an itemize to be a circle

\renewcommand{\labelitemii}{$\circ$}

Use alphabetic letters in enumerations instead of numbers

\renewcommand{\theenumi}{\alph{enumi}}

Change the alignment of the bullet points

\setlength{\leftmargini}{1em}

Give a title to a theorem

\begin{theorem}[Fermat's theorem]

Define a new theorem-type environment

\newtheorem{lemma}{Lemma}

To write a proof, it's possible to create a new environment

\newenvironment{proof} 
               {\noindent \textit{\textbf{Proof.}}~ }     % begin proof
               {\hfill\rule{2mm}{2mm} \vspace{\parskip} } % end proof

Otherwise, the package amsthm provides a proof environment.

Create a table of contents

\tableofcontents

The table of contents will be positioned where the command has been used.

Rename the table of contents from the default 'Contents'

\renewcommand{\contentsname}{Table of Contents}

Provide and optional title to be used in the table of contents

\section[optionaltitle]{sectiontitle}

Add a line to the table of contents

\section*{sectiontitle}
\addcontentsline{toc}{section}{sectiontitle}

Define an abstract

\begin{abstract}
  %
  % [...]
  %
\end{abstract}

Rename the abstract from the default 'Abstract'

\renewcommand{\abstractname}{Acknowledgements}

Use roman page numbers

\pagenumbering{roman}

Return to use arabic numbers

\pagenumbering{arabic}

Write a bibliography

\begin{thebibliography}{99}
\bibitem{wright} Wright, S.J. (1997),
                 {\em Primal-dual interior-point methods},
                 SIAM, Philadelphia.
\end{thebibliography}

The parameter {99} is used when there are 10 or more references. If there are less than 10, then use {9}.

Include a bibliography in bibtex format, saved in bibliographyfile.bib

\bibliographystyle{plain}
\bibliography{bibliographyfile}

Other available styles

\bibliographystyle{alpha}
\bibliographystyle{unsrt}
\bibliographystyle{abbrv}

Cite a reference

\cite{wright}

Specify some pages in a reference

\cite[pp. 120--125]{wright}

To draw a table, use the tabular environment. The parameters of the environment specify the alignment of the column: centered (c), left aligned (l) or right-aligned (r). A vertical bar (|) can be used to print a column separator. A row separator is printed with the command \hline.

\begin{tabular}{|l|c|c|c|}       \hline
   Sales &  1   &  2   &  3   \\ \hline
   North & 2552 & 2770 & 2518 \\
   South & 2548 & 2600 & 2522 \\
   West  & 2569 & 2805 & 2511 \\
   East  & 2569 & 3571 & 2712 \\ \hline
\end{tabular}

To have an entry that spans more than one column, use the command \multicolumn, specifying how many columns to span, the alignment, and the text.

\begin{tabular}{|l|c|c|c|} \hline
         & \multicolumn{3}{c|}{Sales} \\ \cline{2-4}
   Total & 6738 & 8954 & 7512 \\ \hline
\end{tabular}

To print a row separator only between certain columns, use the command \cline, specifying the columns.

\begin{tabular}{|l|c|c|c|}       \hline
   Sales &  1   &  2   &  3   \\ \cline{2-4}
   Total & 6738 & 8954 & 7512 \\ \hline
\end{tabular}

The \raisebox command can be used to move up or down some text.

\begin{tabular}{|l|c|c|c|}       \hline
  \raisebox{-1.5ex}{Sales} &  1   &  2   &  3   \\ \cline{2-4}
                           & 6738 & 8954 & 7512 \\ \hline
\end{tabular}

This may enlarge the row in which it appears, creating some unwanted white space. To avoid it, it's possible to give some optional parameters to \raisebox.

\begin{tabular}{|l|c|c|c|}       \hline
  \raisebox{-1.5ex}[0ex][-1.5ex]{Sales} &  1   &  2   &  3   \\ \cline{2-4}
                                        & 6738 & 8954 & 7512 \\ \hline
\end{tabular}

To center horizonally the table, enclose the tabular environment inside a center environment.

\begin{center}
\begin{tabular}
   [...]
\end{tabular}
\end{center}

To change the spacing of the columns, and shrink them

\setlength{\tabcolsep}{4.2pt}

To draw a graph (nodes and arcs), use the package pst-node.

\[
  \begin{psmatrix}[colsep=4em,rowsep=2ex,mnode=circle,framesep=2ex]
                    & [name=I]{\bf 2} \\ [0pt]
    [name=A]{\bf 1} &                 & [name=C]{\bf 3}
  \psset{arrows=->,arrowscale=2,nodesep=1pt}
  \ncarc[arcangle=20]{A}{I}  \Aput{\frac{1}{2}}
  \ncarc[arcangle=-20]{C}{I} \Bput{\frac{1}{2}}
  \end{psmatrix}
\]

Here is another example

\[
  \begin{psmatrix}[colsep=3em,rowsep=4ex,mnode=circle,framesep=2ex]
   & [name=A]{\bf 1}             & [name=B]{\bf 2} \\
   & [name=F,colsep=-2em]{\bf 6} &                 & [name=C,colsep=0]{\bf 3} \\
   & [name=E]{\bf 5}             & [name=D]{\bf 4}
   \psset{arrows=->,arrowscale=2,nodesep=2pt}
   \ncline{A}{B}
   \ncline{B}{C}
   \ncline{C}{A}
   \ncline{D}{E}
   \ncline{E}{F}
   \ncline{F}{D}
   \ncline[linestyle=dashed]{A}{F}
   \ncline[linestyle=dashed]{E}{B}
  \end{psmatrix}
\]

Use the seminar class

\documentclass[a4]{seminar}
\input{seminar.bug}

Define a slide

\begin{slide}
  %
  % [...]
  %
\end{slide}

To define the frame style

\usepackage{fancybox}
\slideframe{shadow}

Other available styles

\slideframe{double}
\slideframe{plain}
\slideframe{oval}
\slideframe{none}

A macro to create the title of the slide

\newcommand{\slidetitle}[1]
{
  \begin{center}
    \textbf{#1}\vspace{-3ex}
  \end{center}
  \rule{\linewidth}{0.3mm}%\\[0.2ex]
}

This macro centers the title and adds a horizontal line underneath it, and can be used like this

\slidetitle{title}

To create a pdf file with good fonts and correct paper orientation

dvips -Ppdf slides.tex -o
ps2pdf slides.ps slides.pdf

Use calligraphic letters in the math environment

\mathcal{N}

To change the size in the math environment, use one of these commands

\displaystyle
\textstyle
\scriptstyle
\scriptscriptstyle

Write a Linear Programming problem in standard form

\[ \begin{array}{rl}
    \min        & c^Tx \\
    \mbox{s.t.} & Ax = b \\
                & x \ge 0.
    \end{array}
\]

Write a matrix

\[
A = \left[ \begin{array}{cc}
    \tilde{A} & 0 \\ Q & T \\
    \end{array} \right]
\]

Insert section number in equations

\usepackage{amsmath}
\numberwithin{equation}{section}

Add automatically quotation marks around a quotation

\renewenvironment{quotation}
   {\begin{quote}\singlespace
    ``\sl \ignorespaces}
   {\unskip \rm '' \end{quote}}

Rotate a figure

\includegraphics[angle=45]{file.eps}

Create a framed box

\newcommand{\fb}[1]{
  \begin{center}
    \fbox{\parbox{.9\textwidth}{#1}}
  \end{center}
}

To use it

\fb{Text in the framed box}

For multiline comments use the package verbatim

\usepackage{verbatim}

To use it

\begin{comment}
%
% [...]
%
\end{comment}

To set the label and separation to the left of the caption text

\usepackage[hang]{caption}

To set the depth of the numbering in the sections

\setcounter{secnumdepth}{2}

To set the depth of the numbering in the table of contents

\setcounter{tocdepth}{2}

Change the .emacs file in the home directory to run latex commands directly from emacs

(setq tex-default-mode 'latex-mode       
 tex-run-command "latex"
 tex-dvi-view-command "xdvi"
 tex-dvi-print-command "dvips")

Now, using C-c C-f will compile the latex file.

Two graphs can appear in one figure by using the subfig package

\begin{figure}
\subfloat[First figure caption]{\includegraphics{file1.eps}}
\hfill
\subfloat[Second figure caption]{\includegraphics{file2.eps}}
\caption{Caption for both figures}
\end{figure}