$\LaTeX$

Introduction

LaTeX, also stylized as $\LaTeX$, is a software based on the typesetting system $\TeX$ which was developed by computer scientist and Stanford University professor Donald Knuth and first released in 1978. It is widely used in academia, especially in STEM fields, because it allows everyone to produce high-quality papers and books with little effort. The most useful features of LaTeX include the following.

• Typesetting special characters like $\varepsilon$ or $\int_0^1 x^2 \mathrm{d}x$ or $\sum_{j=0}^N j$ is easy.

• Figures, tables, sections, pages, etc. are enumerated automatically and updated whenever you compile your document.

• LaTeX deals with your citations and handles the bibliography.

WYSIWYG versus WYSIWYAF

After writing a document with a word processing software like MS Word the printed version of it looks like a copy of what you saw on the monitor. One could also say that "What You See Is What You Get". In contrast, LaTeX uses plain text and macros (commands) to translate your "scripted" document into a PDF which looks nothing like what you saw. Hence, "What You See Is What You Asked For".

In the beginning remembering the individual LaTeX commands by heart might seem difficult. But quite soon you will notice that letting LaTeX handle all the tedious things like, e.g., formatting the document is actually worth the effort.

Compiling a Document

Download and install a TeX distribution like MiKTeX or TeX Live and (optionally) an IDE, for example TeXnicCenter. Put the following in a main.tex file

\documentclass[12pt]{article}

\begin{document}
Hello World!
\end{document}

and compile it using

pdflatex main.tex

The output is a white sheet with "Hello World!" written on top of it and the number of the page at the bottom. Notice how LaTeX inserted this number automatically?

Basic Syntax

Comment lines start with an %. There are no multi-line comments. Every LaTeX command starts with a backslash \somecommand. Every document starts with a definition of its type.

\documentclass[12pt]{article}

Other possible document types include but are not limited to book, report, presentations, etc. The options for the document appear in the [] brackets. In this case we want to use 12pt font.

If you want to include graphics, colored text, or source code from another language into your document, you need to enhance the capabilities of LaTeX. This is done by adding packages.

\usepackage{caption}
\usepackage{float}
\usepackage{hyperref}
...

Providing information about the title page is as simple as setting the following variables.

\author{John Doe \& \\
Jane Doe}
\date{\today}
\title{Reporting ULG 2023}

Everything we have seen so far belongs to the so-called preamble. The actual document begins with the keyword

\begin{document}

We can let LaTeX create a title page based on the information we provided above and add a table of contents with

\maketitle

\tableofcontents

Adding new sections, subsections, and subsubsections is intuitive.

\section{First Section}
\section{Another section}
\subsection{First Subsection}
\subsubsection{First Subsubsection}

If you would like to suppress the numbering just add an asterisk after the keyword.

\section*{Unnumbered Section}
\subsection*{Unnumbered Subsection}
\subsubsection*{Unnumbered Subsubsection}

With LaTeX you can label pretty much anything from figures to sections to tables. Let us assume you would like to refer to some previous section in another section of your document. Just label the command and refer to it accordingly. Try and provide a unique informative label.

\section{Previous Section}\label{sec:previous}

\section{Some Other Section}
This is a reference the previous Section~\ref{sec:previous}.

Lists are one of the easiest things to create in LaTeX. Just wrap the items inside of an enumerate environment if you want to have numbers

\begin{enumerate} % This creates an "enumerate" environment.
  % \item tells the enumerate to increment
  \item First item.
  \item Second item.
\end{enumerate} % All environments must have an end.

or an itemize environment if you need bullet points

\begin{itemize} % This creates an "itemize" environment.
  \item First bullet point.
  \item Second bullet point.
\end{itemize}

Mathematics

Many people use LaTex for its abundance of special symbols and characters especially in mathematics. These include set and relation symbols, arrows, operators, and Greek letters just to name a few. You enter the in-line math mode with dollar signs $x$ and the regular math mode with

\[
    a + b = c
\]

Here is a very incomplete list of the most commonly used mathematical symbols.

• Quantifiers in logic

  Syntax	Output
  $\forall$	$\forall$
  $\exists$	$\exists$
  $\exists!$	$\exists!$
  $\neg$	$\neg$
  $\nexists$	$\nexists$

• Sets and relations

  Syntax	Output
  $\subset$	$\subset$
  $\not\subset$	$\not\subset$
  $\supset$	$\supset$
  $\not\supset$	$\not\supset$
  $\gg$	$\gg$
  $\geq$	$\geq$
  $\ll$	$\ll$
  $\leq$	$\leq$
  $\approx$	$\approx$
  $\neq$	$\neq$

• Greek alphabet

  Syntax	Output
  $\alpha$	$\alpha$
  $\beta$	$\beta$
  $\gamma$	$\gamma$
  $\ldots$	$\ldots$

• Common functions

  Syntax	Output
  $\sin$	$\sin$
  $\cos$	$\cos$
  $\tan$	$\tan$
  $\log$	$\log$
  $\exp$	$\exp$

• Miscellaneous

  Syntax	Output
  $\int_0^1$	$\int_0^1$
  $\sum_{j=0}^N j$	$\sum_{j=0}^N j$
  $\prod_{j=1}^N j$	$\prod_{j=1}^N j$
  $\frac{a}{b}$	$\frac{a}{b}$

We can also insert equations in an "equation environment"

\begin{equation}\label{eq:pythagoras} % for referencing
    a^2 + b^2 = c^2
\end{equation}

and reference to it using \ref{eq:pythagoras}. It is best practice to use these labels for different things.

Tables

With the booktabs package you can create beautiful tables with LaTeX. The syntax is quite self-explanatory.

\begin{tabular}{c|cc}  % centered, vertical line, centered, centered
    \toprule
    A & B & C \\
    \midrule
    1 & ULG & 2023 \\
    2 & Foo & Bar
    \bottomrule
\end{tabular}