LaTeX Skill

1. Overview

LaTeX is a markup language and typesetting system for producing high-quality documents. It excels at structured documents with complex formatting, mathematics, cross-references, and bibliographies.

When to use LaTeX:

• Academic papers, journal submissions
• Theses and dissertations
• Technical documentation
• CVs and résumés
• Presentations (Beamer)
• Books, reports, letters

Key concepts:

Concept	Description
Preamble	Everything before \begin{document} — class, packages, settings
Document body	Content between \begin{document} and \end{document}
Commands	Start with \, e.g. \textbf{bold}. Optional args in [], required in {}
Environments	\begin{name}...\end{name} blocks for scoped formatting
Packages	Extensions loaded with \usepackage{name} in the preamble

2. Document Structure

Document Classes

\documentclass[options]{class}

Class	Use case
article	Short documents, papers, assignments
report	Longer documents with chapters
book	Books (front/back matter, chapters)
beamer	Presentations/slides
letter	Formal letters
memoir	Flexible — replaces article/report/book

Common Class Options

\documentclass[12pt,a4paper,twocolumn,draft]{article}

Option	Values
Font size	10pt, 11pt, 12pt
Paper	a4paper, letterpaper, a5paper
Columns	onecolumn, twocolumn
Sides	oneside, twoside
Draft	draft (shows overfull boxes, skips images)

Minimal Document

\documentclass[12pt,a4paper]{article}

% === PREAMBLE ===
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath, amssymb}
\usepackage{graphicx}
\usepackage{hyperref}

\title{My Document}
\author{Author Name}
\date{\today}

% === BODY ===
\begin{document}
\maketitle
\tableofcontents

\section{Introduction}
Content here.

\end{document}

3. Text Formatting

Style Commands

Command	Result
\textbf{text}	bold
\textit{text}	italic
\underline{text}	underlined
\emph{text}	emphasis (italic, or upright if already italic)
\texttt{text}	monospace
\textsc{text}	SMALL CAPS
\textsf{text}	sans-serif

Font Sizes

Smallest to largest:

\tiny  \scriptsize  \footnotesize  \small  \normalsize
\large  \Large  \LARGE  \huge  \Huge

Use as: {\large This text is large.} or as environment.

Font Families

Command	Declaration	Family
\textrm{}	\rmfamily	Serif (Roman)
\textsf{}	\sffamily	Sans-serif
\texttt{}	\ttfamily	Monospace

Alignment

\begin{center}    Centered text.    \end{center}
\begin{flushleft} Left-aligned.     \end{flushleft}
\begin{flushright} Right-aligned.   \end{flushright}

Or inline: \centering, \raggedright, \raggedleft

Spacing

\vspace{1cm}          % vertical space
\hspace{2em}          % horizontal space
\vfill                % stretch vertical
\hfill                % stretch horizontal
\\[0.5cm]             % line break with extra space
\setlength{\parskip}{0.5em}   % paragraph spacing
\setlength{\parindent}{0pt}   % remove paragraph indent
\noindent             % suppress indent for one paragraph

Line spacing (requires setspace package):

\usepackage{setspace}
\onehalfspacing    % or \doublespacing, \singlespacing

Special Characters

These characters must be escaped:

Character	LaTeX	Character	LaTeX
%	\%	$	\$
&	\&	#	\#
_	\_	{	\{
}	\}	~	\textasciitilde
^	\textasciicircum	\	\textbackslash

4. Document Organization

Sectioning

\part{Part Title}           % only in report/book
\chapter{Chapter Title}     % only in report/book
\section{Section}
\subsection{Subsection}
\subsubsection{Subsubsection}
\paragraph{Paragraph}
\paragraphsub{Subparagraph}

Starred versions (\section*{}) suppress numbering and TOC entry.

Table of Contents

\tableofcontents    % requires two compilations
\listoffigures
\listoftables

Lists

% Bulleted
\begin{itemize}
  \item First item
  \item Second item
\end{itemize}

% Numbered
\begin{enumerate}
  \item First
  \item Second
\end{enumerate}

% Labeled
\begin{description}
  \item[Term] Definition here.
\end{description}

Customize with enumitem package:

\usepackage{enumitem}
\begin{enumerate}[label=(\alph*), start=1]

Cross-References

\section{Methods}\label{sec:methods}
See Section~\ref{sec:methods} on page~\pageref{sec:methods}.

With hyperref, use \autoref{sec:methods} for automatic "Section 2" text.

Rule: Always place \label after \caption (in floats) or after the sectioning command.

Footnotes

This has a footnote.\footnote{Footnote text here.}

5. Mathematics

Inline vs Display

Inline: $E = mc^2$ or \(E = mc^2\)

Display:
\[ E = mc^2 \]

% Numbered equation:
\begin{equation}\label{eq:einstein}
  E = mc^2
\end{equation}

Essential Packages

\usepackage{amsmath}    % align, cases, matrices, etc.
\usepackage{amssymb}    % extra symbols (ℝ, ℤ, etc.)
\usepackage{mathtools}  % extends amsmath (dcases, coloneqq, etc.)

Common Constructs

% Fractions
\frac{a}{b}          \dfrac{a}{b}  (display-size)

% Roots
\sqrt{x}             \sqrt[3]{x}

% Sub/superscripts
x_{i}   x^{2}   x_{i}^{2}   a_{i,j}

% Sums, products, integrals
\sum_{i=1}^{n} x_i      \prod_{i=1}^{n} x_i
\int_{0}^{\infty} f(x)\,dx
\lim_{x \to \infty} f(x)

% Brackets (auto-sized)
\left( \frac{a}{b} \right)
\left[ ... \right]
\left\{ ... \right\}

Matrices

\begin{pmatrix} a & b \\ c & d \end{pmatrix}   % (a b; c d)
\begin{bmatrix} a & b \\ c & d \end{bmatrix}   % [a b; c d]
\begin{vmatrix} a & b \\ c & d \end{vmatrix}   % |a b; c d| (determinant)
\begin{Bmatrix} a & b \\ c & d \end{Bmatrix}   % {a b; c d}

Aligned Equations

\begin{align}
  f(x) &= x^2 + 2x + 1 \label{eq:f} \\
  g(x) &= x^3 - 1       \label{eq:g}
\end{align}

% No numbering:
\begin{align*}
  a &= b + c \\
  d &= e + f
\end{align*}

Cases

f(x) = \begin{cases}
  x^2  & \text{if } x \geq 0 \\
  -x^2 & \text{if } x < 0
\end{cases}

Greek Letters

Lower	Command	Upper	Command
α	\alpha	Α	A
β	\beta	Β	B
γ	\gamma	Γ	\Gamma
δ	\delta	Δ	\Delta
ε	\epsilon, \varepsilon	Ε	E
θ	\theta	Θ	\Theta
λ	\lambda	Λ	\Lambda
μ	\mu	—	—
π	\pi	Π	\Pi
σ	\sigma	Σ	\Sigma
φ	\phi, \varphi	Φ	\Phi
ω	\omega	Ω	\Omega

Common Math Symbols

Symbol	Command	Symbol	Command
≤	\leq	≥	\geq
≠	\neq	≈	\approx
±	\pm	×	\times
÷	\div	·	\cdot
∈	\in	∉	\notin
⊂	\subset	⊆	\subseteq
∪	\cup	∩	\cap
∞	\infty	∂	\partial
∇	\nabla	∀	\forall
∃	\exists	→	\to, \rightarrow
⇒	\Rightarrow	⇔	\Leftrightarrow
ℝ	\mathbb{R}	ℤ	\mathbb{Z}
…	\dots, \ldots, \cdots

6. Tables

Basic Table

\begin{table}[htbp]
  \centering
  \caption{Results summary}\label{tab:results}
  \begin{tabular}{lcrp{4cm}}
    \toprule
    Name & Count & Score & Description \\
    \midrule
    Alpha & 10 & 95.2 & First entry \\
    Beta  & 20 & 87.1 & Second entry \\
    \bottomrule
  \end{tabular}
\end{table}

Column Specifiers

Spec	Alignment
l	Left
c	Center
r	Right
p{width}	Paragraph (top-aligned, fixed width)
m{width}	Middle-aligned paragraph (requires array)
`	`

Key Packages

\usepackage{booktabs}   % \toprule, \midrule, \bottomrule (professional rules)
\usepackage{multirow}   % \multirow{nrows}{width}{text}
\usepackage{longtable}  % tables spanning multiple pages
\usepackage{tabularx}   % auto-width X columns

Multi-column/row

\multicolumn{3}{c}{Spanning header} \\
\multirow{2}{*}{Tall cell}

7. Figures and Images

\usepackage{graphicx}

\begin{figure}[htbp]
  \centering
  \includegraphics[width=0.8\textwidth]{images/photo.png}
  \caption{A descriptive caption.}\label{fig:photo}
\end{figure}

includegraphics Options

Option	Example
width	width=0.5\textwidth
height	height=5cm
scale	scale=0.75
angle	angle=90
trim	trim=1cm 2cm 1cm 2cm, clip (left bottom right top)

Float Placement

Specifier	Meaning
h	Here (approximately)
t	Top of page
b	Bottom of page
p	Dedicated float page
!	Override internal limits
H	Exactly here (requires float package)

Subfigures

\usepackage{subcaption}

\begin{figure}[htbp]
  \centering
  \begin{subfigure}[b]{0.48\textwidth}
    \includegraphics[width=\textwidth]{img1.png}
    \caption{First}\label{fig:sub1}
  \end{subfigure}
  \hfill
  \begin{subfigure}[b]{0.48\textwidth}
    \includegraphics[width=\textwidth]{img2.png}
    \caption{Second}\label{fig:sub2}
  \end{subfigure}
  \caption{Both images}\label{fig:both}
\end{figure}

8. Bibliographies and Citations

BibTeX Workflow

1. Create references.bib:

@article{smith2023,
  author  = {Smith, John and Doe, Jane},
  title   = {An Important Paper},
  journal = {Journal of Examples},
  year    = {2023},
  volume  = {42},
  pages   = {1--15},
  doi     = {10.1234/example}
}

@book{knuth1984,
  author    = {Knuth, Donald E.},
  title     = {The {\TeX}book},
  publisher = {Addison-Wesley},
  year      = {1984}
}

2. In document:

\usepackage{natbib}  % or use biblatex
\bibliographystyle{plainnat}

As shown by \citet{smith2023}...  % Smith and Doe (2023)
This is known \citep{smith2023}.  % (Smith and Doe, 2023)

\bibliography{references}

3. Compile: pdflatex → bibtex → pdflatex → pdflatex

BibLaTeX Workflow (Modern)

\usepackage[backend=biber, style=authoryear]{biblatex}
\addbibresource{references.bib}

\textcite{smith2023}   % Smith and Doe (2023)
\parencite{smith2023}  % (Smith and Doe, 2023)

\printbibliography

Compile: pdflatex → biber → pdflatex → pdflatex

natbib vs biblatex

Feature	natbib	biblatex
Backend	BibTeX	Biber (recommended)
Flexibility	Limited styles	Highly customizable
Unicode	Poor	Full support
Recommendation	Legacy projects	New projects

9. Code Listings

verbatim

\begin{verbatim}
def hello():
    print("Hello, world!")
\end{verbatim}

Inline: \verb|some_code()|

listings Package

\usepackage{listings}
\usepackage{xcolor}

\lstdefinestyle{mystyle}{
  basicstyle=\ttfamily\small,
  keywordstyle=\color{blue},
  commentstyle=\color{gray},
  stringstyle=\color{red},
  numbers=left,
  numberstyle=\tiny,
  frame=single,
  breaklines=true
}

\begin{lstlisting}[language=Python, style=mystyle, caption={Example}]
def factorial(n):
    """Compute factorial."""
    if n <= 1:
        return 1
    return n * factorial(n - 1)
\end{lstlisting}

minted Package (Prettier, Requires Pygments)

\usepackage{minted}

\begin{minted}[linenos, frame=lines, fontsize=\small]{python}
def factorial(n):
    if n <= 1:
        return 1
    return n * factorial(n - 1)
\end{minted}

Compile with: pdflatex -shell-escape document.tex

10. Presentations (Beamer)

\documentclass{beamer}
\usetheme{Madrid}          % or: Berlin, Warsaw, Metropolis, etc.
\usecolortheme{default}    % or: beaver, crane, dolphin, etc.

\title{My Presentation}
\author{Author}
\date{\today}

\begin{document}

\begin{frame}
  \titlepage
\end{frame}

\begin{frame}{Outline}
  \tableofcontents
\end{frame}

\section{Introduction}
\begin{frame}{Introduction}
  \begin{itemize}
    \item<1-> First point (appears on slide 1+)
    \item<2-> Second point (appears on slide 2+)
    \item<3-> Third point
  \end{itemize}
\end{frame}

\begin{frame}{With Columns}
  \begin{columns}
    \begin{column}{0.5\textwidth}
      Left content
    \end{column}
    \begin{column}{0.5\textwidth}
      Right content
    \end{column}
  \end{columns}
\end{frame}

\end{document}

Popular themes: Madrid, Berlin, Metropolis (modern, clean), Warsaw, CambridgeUS

Overlay Commands

Command	Effect
\pause	Show content incrementally
\onslide<2>{text}	Show on slide 2 only
\only<1>{text}	Only on slide 1 (no space reserved)
\visible<2->{text}	Visible from slide 2 onward
\alert<2>{text}	Highlighted on slide 2

11. Page Layout

Margins (geometry)

\usepackage[margin=2.5cm]{geometry}
% or:
\usepackage[top=3cm, bottom=3cm, left=2cm, right=2cm]{geometry}

Headers and Footers (fancyhdr)

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}                          % clear all
\fancyhead[L]{Left Header}
\fancyhead[R]{\rightmark}          % current section
\fancyfoot[C]{\thepage}            % page number center
\renewcommand{\headrulewidth}{0.4pt}

Page Numbering

\pagenumbering{roman}   % i, ii, iii (for front matter)
\pagenumbering{arabic}  % 1, 2, 3 (for main content)
\thispagestyle{empty}   % no number on this page

Multi-Column

\usepackage{multicol}
\begin{multicols}{2}
  Content in two columns...
\end{multicols}

12. Common Packages Reference

Package	Purpose
amsmath	Enhanced math environments
amssymb	Extra math symbols (ℝ, ℤ, etc.)
mathtools	Extensions to amsmath
graphicx	Image inclusion
hyperref	Clickable links, PDF metadata
geometry	Page margins and dimensions
booktabs	Professional table rules
multirow	Multi-row table cells
longtable	Multi-page tables
tabularx	Auto-width table columns
xcolor	Color support
listings	Code listings
minted	Syntax-highlighted code (needs Pygments)
tikz	Programmatic graphics and diagrams
pgfplots	Data plots (built on TikZ)
fancyhdr	Custom headers/footers
setspace	Line spacing
enumitem	Customize list environments
subcaption	Subfigures and subtables
float	Extra float control ([H] placement)
babel	Language/hyphenation support
inputenc	Input encoding (utf8)
fontenc	Font encoding (T1)
microtype	Microtypographic enhancements
cleveref	Smart cross-references (\cref)
siunitx	SI units and number formatting
algorithm2e	Algorithm pseudocode
natbib	Citation management
biblatex	Modern bibliography management
csquotes	Context-sensitive quotation marks
url	Typeset URLs
caption	Customize caption formatting
appendix	Appendix management

Load order tip: Load hyperref last (or near-last). Exceptions: cleveref goes after hyperref.

13. Compilation

Engines

Engine	Use when
pdflatex	Default. Most compatible. ASCII/Latin input.
xelatex	System fonts (TTF/OTF), full Unicode
lualatex	System fonts + Lua scripting, full Unicode

Compilation Sequence

# Basic document
pdflatex document.tex

# With bibliography (BibTeX)
pdflatex document.tex
bibtex document
pdflatex document.tex
pdflatex document.tex

# With bibliography (Biber/BibLaTeX)
pdflatex document.tex
biber document
pdflatex document.tex
pdflatex document.tex

# Automated (recommended)
latexmk -pdf document.tex           # pdflatex
latexmk -xelatex document.tex       # xelatex
latexmk -lualatex document.tex      # lualatex
latexmk -pdf -pvc document.tex      # continuous preview

Common Errors and Fixes

Error	Cause	Fix
Undefined control sequence	Typo or missing package	Check spelling; add \usepackage
Missing $ inserted	Math symbol outside math mode	Wrap in $...$
Missing \begin{document}	Error in preamble	Check preamble for typos
File not found	Wrong path or missing file	Check filename/path, check extension
Overfull \hbox	Line too wide	Rephrase, add \allowbreak, or use \sloppy
Undefined citation	Missing bib entry or no bibtex run	Run bibtex/biber, check .bib keys
Too many unprocessed floats	Too many figures queued	Add \clearpage or use [H]
Dimension too large	Image scaling issue	Check width/height values
Package clash	Two packages conflict	Load one, check docs for compatibility

Reading Log Files

• Look at the .log file for full error context
• Errors show as ! lines
• Warnings show as LaTeX Warning: or Package xyz Warning:
• Rerun to get cross-references right → compile again

14. Tips and Best Practices

1. Multi-file projects: Use \input{chapters/intro} (inserts inline) or \include{chapters/intro} (adds \clearpage, enables \includeonly)
2. Custom preamble: Move package loading to preamble.sty or preamble.tex, then \input{preamble}
3. Label after caption: \caption{...}\label{fig:x} — never the reverse
4. Non-breaking spaces: Figure~\ref{fig:x}, Section~\ref{sec:y} — prevents linebreak before number
5. Draft mode: \documentclass[draft]{article} — speeds compilation, shows overfull boxes
6. Use \centering not center inside floats (avoids extra vertical spacing)
7. Avoid \\ for paragraph breaks — use blank lines instead
8. Use booktabs — never \hline and vertical lines for professional tables
9. Use microtype — improves typography with zero effort
10. Use cleveref — \cref{fig:x} auto-generates "Figure 1" text
11. Version control: LaTeX is plain text — use Git
12. One sentence per line — makes diffs cleaner in version control

15. Quick Reference

Most Common Commands

Task	Command
Bold	\textbf{text}
Italic	\textit{text}
Monospace	\texttt{text}
Section	\section{Title}
Reference	\ref{label}
Citation	\cite{key}
Footnote	\footnote{text}
Image	\includegraphics[width=\textwidth]{file}
URL	\url{https://...} or \href{url}{text}
List item	\item
New page	\newpage or \clearpage
Comment	% comment
Math inline	$E=mc^2$
Math display	\[ E=mc^2 \]
Fraction	\frac{a}{b}

Math Operators

Command	Symbol	Command	Symbol
\sin	sin	\cos	cos
\tan	tan	\log	log
\ln	ln	\exp	exp
\min	min	\max	max
\lim	lim	\sum	Σ
\prod	Π	\int	∫

Arrows

Command	Symbol
\rightarrow, \to	→
\leftarrow	←
\leftrightarrow	↔
\Rightarrow	⇒
\Leftarrow	⇐
\Leftrightarrow	⇔
\mapsto	↦
\uparrow	↑
\downarrow	↓

References

• LaTeX Project Documentation
• Overleaf Learn
• CTAN — Comprehensive TeX Archive Network
• LaTeX2e: An unofficial reference manual
• Detexify — Draw a symbol, find the command