# Using \mathsection in the chapter

How can I use LaTeX to get the result like the following picture?

In this picture, $\mathsection{1} Hình thang và hình bình hành$ is the title of the first section. If I use \mathsection and \section, then the result is

My question is: What is the code that gives me the result like the first picture?

You can redefine \@makechapterhead, \@makeschapterhead and \@sect to obtain the desired representation for the headings (using a package like titlesec here is not possible since it's not compatible with the AMS document classes):

\documentclass[11pt,a4paper]{amsbook}

\makeatletter
\begingroup
\fontsize{\@xivpt}{18}\bfseries\centering
\ifnum\c@secnumdepth>\m@ne
\leavevmode \hskip-\leftskip
\rlap{\vbox to\z@{\vss
\centerline{\normalsize\mdseries
\@xp{\scshape{\chaptername}}\enspace\thechapter}
\vskip 2pc}}\hskip\leftskip\fi
\normalfont\scshape#1\par \endgroup
\vskip\skip@ }
\begingroup
\fontsize{\@xivpt}{18}\normalfont\scshape\centering
#1\par \endgroup
\vskip\skip@ }
\def\@sect#1#2#3#4#5#6[#7]#8{%
\edef\@toclevel{\ifnum#2=\@m 0\else\number#2\fi}%
\ifnum #2>\c@secnumdepth \let\@secnumber\@empty
\else \@xp\let\@xp\@secnumber\csname the#1\endcsname\fi
\ifnum #2>\c@secnumdepth
\let\@svsec\@empty
\else
\refstepcounter{#1}%
\edef\@svsec{\ifnum#2<\@m
\@ifundefined{#1name}{}{%
\ignorespaces\csname #1name\endcsname\space}\fi
\@nx\textup{%
\csname the#1\endcsname.}\enspace
}%
\fi
\@tempskipa #5\relax
\ifdim \@tempskipa>\z@ % then this is not a run-in section heading
\begingroup\ifnum#2=1 \noindent\textbf{\S}\fi#6\relax% NEW
\@hangfrom{\hskip #3\relax\@svsec}{\interlinepenalty\@M #8\par}%
\endgroup
\csname #1mark\endcsname{#7}%
\ifnum#2>\@m \else \@tocwrite{#1}{#8}\fi
\else
\def\@svsechd{#6\hskip #3\@svsec
\@ifnotempty{#8}{\ignorespaces#8\unskip
\ifnum#2>\@m \else \@tocwrite{#1}{#8}\fi
}%
\fi
\global\@nobreaktrue
\@xsect{#5}}
\def\section{\@startsection{section}{1}%
\z@{.7\linespacing\@plus\linespacing}{.5\linespacing}
{\normalfont\bfseries}}
\makeatother

\begin{document}

\chapter{Test Chapter}
\section{Test Numbered Section}
\section*{Test Unnumbered Section}

\end{document}


• How can I customize the word Chapter since in my original file when I type chapter it gave me "Chương"(which is chapter in my native language). But when I add your titleformat, it gave me Chapter rather than "Chương". So how can I customize your titleformat command to keep the word "Chương" ? – Knumber10 Apr 10 '13 at 3:16
• @Nguyễn Duy Khánh which document class are you using? Are you loading the babel package? If so, with what language option? – Gonzalo Medina Apr 10 '13 at 4:36
• @NguyễnDuyKhánh Replace \chaptertitlename with \chaptername in my code; this should give you "Chương" again; if not, let me know to find a solution. – Gonzalo Medina Apr 10 '13 at 21:44