% chap1.tex (Chapter 1 of my thesis)
\Chapter{INTRODUCTION}
\label{intro}
\section{The Problem}
\label{intro:prob}
Here's the problem I'm trying to solve.
\subsection{Background}
\label{intro:prob:bkgd}
Here's some background on the problem, the model for which is described
in section~\ref{intro:prob:model}.
\subsection{The Model}
\label{intro:prob:model}
Here's the model I'm using for the problem, whose background is mentioned
in section~\ref{intro:prob:bkgd}. Here's a lemma important to the model
(for the proof, see Appendix~\ref{app:proof:easy}):
\begin{lemma}
\label{easylemma}
This is a Lemma.
\end{lemma}
\section{Previous Approaches}
Here are some previous approaches to this problem, which is defined in
section~\ref{intro:prob}.