back to liberal spaces of official syntax (in contrast to 4b190c763097), e.g. relevant for easychair.bib;
\documentclass[12pt,a4paper,fleqn]{report}
\usepackage[T1]{fontenc}
\usepackage{amssymb}
\usepackage{eurosym}
\usepackage[english]{babel}
\usepackage[only,bigsqcap]{stmaryrd}
\usepackage{textcomp}
\usepackage{latexsym}
\usepackage{graphicx}
\let\intorig=\int %iman.sty redefines \int
\usepackage{iman,extra,isar,proof}
\usepackage[nohyphen,strings]{underscore}
\usepackage{isabelle}
\usepackage{isabellesym}
\usepackage{railsetup}
\usepackage{ttbox}
\usepackage{supertabular}
\usepackage{style}
\usepackage{pdfsetup}
\hyphenation{Isabelle}
\hyphenation{Isar}
\isadroptag{theory}
\title{\includegraphics[scale=0.5]{isabelle_isar} \\[4ex] The Isabelle/Isar Reference Manual}
\author{\emph{Makarius Wenzel} \\[3ex]
With Contributions by
Clemens Ballarin,
Stefan Berghofer, \\
Jasmin Blanchette,
Timothy Bourke,
Lukas Bulwahn, \\
Amine Chaieb,
Lucas Dixon,
Florian Haftmann, \\
Brian Huffman,
Lars Hupel,
Gerwin Klein, \\
Alexander Krauss,
Ond\v{r}ej Kun\v{c}ar,
Andreas Lochbihler, \\
Tobias Nipkow,
Lars Noschinski,
David von Oheimb, \\
Larry Paulson,
Sebastian Skalberg,
Christian Sternagel
}
\makeindex
\chardef\charbackquote=`\`
\newcommand{\backquote}{\mbox{\tt\charbackquote}}
\begin{document}
\maketitle
\pagenumbering{roman}
{\def\isamarkupchapter#1{\chapter*{#1}}\input{Preface.tex}}
\tableofcontents
\clearfirst
\part{Basic Concepts}
\input{Synopsis.tex}
\input{Framework.tex}
\input{First_Order_Logic.tex}
\part{General Language Elements}
\input{Outer_Syntax.tex}
\input{Document_Preparation.tex}
\input{Spec.tex}
\input{Proof.tex}
\input{Inner_Syntax.tex}
\input{Misc.tex}
\input{Generic.tex}
\part{Isabelle/HOL}\label{part:hol}
\input{HOL_Specific.tex}
\part{Appendix}
\appendix
\input{Quick_Reference.tex}
\let\int\intorig
\input{Symbols.tex}
\input{ML_Tactic.tex}
\begingroup
\tocentry{\bibname}
\bibliographystyle{abbrv} \small\raggedright\frenchspacing
\bibliography{manual}
\endgroup
\tocentry{\indexname}
\printindex
\end{document}