Latex

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  First point (appears on slide 1+)
    \item Second point (appears on slide 2+)
    \item 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{text} | Show on slide 2 only | | \only{text} | Only on slide 1 (no space reserved) | | \visible{text} | Visible from slide 2 onward | | \alert{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

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: igbuend
• Source: igbuend/grimbard
• License: MIT

Install and usage instructions live in the source repository linked above.