# TexLive Sections and Lists

**Section hierarchy** organizes documents. Articles use `\section{Title}` (level 1), `\subsection{Title}` (level 2), `\subsubsection{Title}` (level 3). Books add `\chapter{Title}` at level 0. Sections are automatically numbered and appear in the table of contents. Use the starred version `\section*{Title}` for unnumbered sections not in the TOC.

```latex
\section{Introduction}
Content here.

\subsection{Background}
More content.

\subsection*{Unnumbered subsection}
This doesn't appear in TOC.

\section{Methods}
```

**Lists** are environments for bullet points or numbered items. `itemize` creates bullet lists, `enumerate` creates numbered lists, `description` creates term-definition pairs.

```latex
\begin{itemize}
  \item First point
  \item Second point
  \begin{itemize}
    \item Nested point
  \end{itemize}
\end{itemize}
```

renders as a bulleted list with nested indentation.

```latex
\begin{enumerate}
  \item First step
  \item Second step
  \item Third step
\end{enumerate}
```

renders as a numbered list: 1, 2, 3.

```latex
\begin{description}
  \item[Term] Definition of term.
  \item[Another] Its definition.
\end{description}
```

renders as a term-definition list.

**Nesting** works by indenting one list environment inside another. The automatic numbering and bullet styles adjust (bullets become dashes, then asterisks at deeper levels). Limit nesting to 3-4 levels for clarity.

**Labels and cross-references** let you reference sections, figures, and tables by number. Place `\label{key}` after the section or caption, then use `\ref{key}` to insert its number:

```latex
\section{Introduction}
\label{sec:intro}

In Section \ref{sec:intro}, we showed...
```

The reference is updated automatically if you move sections. Compile twice for references to resolve.