src/HOL/document/root.tex

clarified document;

\documentclass[11pt,a4paper]{article}
\usepackage{graphicx,isabelle,isabellesym,latexsym}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{textcomp}
\usepackage[english]{babel}
\usepackage[only,bigsqcap]{stmaryrd}
\usepackage[utf8]{inputenc}
\usepackage{pdfsetup}

\urlstyle{rm}
\isabellestyle{it}
\pagestyle{myheadings}

\begin{document}

\title{Isabelle/HOL --- Higher-Order Logic}
\maketitle

\tableofcontents

\begin{center}
  \includegraphics[width=\textwidth,height=\textheight,keepaspectratio]{session_graph}
\end{center}

\newpage

\renewcommand{\setisabellecontext}[1]{\markright{THEORY~``#1''}}

\parindent 0pt\parskip 0.5ex
\input{Code_Generator.tex}
\input{session}

\pagestyle{headings}
\bibliographystyle{abbrv}
\bibliography{root}

\end{document}