%% This document created by Scientific Word (R) Version 2.0
%% Starting shell: book
%%%%%%%%%%%%%%%%%%%%%%%%%%
%\input chitexl
  \catcode`\@=11
  \def\thinhline{\noalign{\ifnum0=`}\fi\hrule \@height \arrayrulewidth
     \futurelet \@tempa\@xhline}
  \def\thickhline{\noalign{\ifnum0=`}\fi\hrule \@height 2\arrayrulewidth
     \futurelet \@tempa\@xhline}
  \def\@xhline{\ifx\@tempa\hline\vskip \doublerulesep\fi
       \ifnum0=`{\fi}}
%%%%%%%%%%%%%%%%%%%%%%%%%%

\documentclass[12pt,thmsa]{book}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{cbook}

\input tcilatex
%\hsize=6.5in
%\textwidth=6.5in
\textheight=6.42in
%\hoffset -1.55cm

\begin{document}
%\mingb
\li

%\pagestyle{headings}  %%%% don't use for sw20obk3.sty %%%%%

\title{\yuan 近\ \, 世\ \, 代\ \, 數\ \\
      Modern Algebra}


\author{\fs Elbert A. Walker 艾伯特\thanks{author 作者} }


\date{6 October 1994}

\maketitle %this should be after abstract in sw20balk.sty


\pskaib

\begin{abstract}
This document describes by example the use of {\tt asaetr.sty}, a \LaTeX\
style that somewhat conforms to the style used in the {\em Transactions of
the ASAE}\/. \cite{dunford} An accompanying BiBTeX style file is also used
to format the bibliography in a style similar to that used by ASAE. 
%\keywords{\LaTeX,\ typesetting, ASAE Transactions.}
\end{abstract}

\mingb


\tableofcontents%
\listoffigures%
\listoftables%


%\part[群 論 特 論]{ 群 論 特 論 Group Theory}

%\psmingb
\chapter[Group Theory 特 論 ]{ 群 論 特 論 Group Theory}


\section[導 論]{導 論 Introduction}

%\chMagnification 1200


群論是一門領域甚廣的學科，幾乎任何數學訓練都需要它。本章將簡單介紹一些%
古典的 非-Abelian 群論。在{\underbar{第二章}}，我們將介紹同構，正規子群，
商群，直和等基本觀念。 ...

\li
群論是一門領域甚廣的學科，幾乎任何數學訓練都需要它。本章將簡單介紹一些%
古典的 非-Abelian 群論。在{\underbar{第二章}}，我們將介紹同構，正規子群，
商群，直和等基本觀念。 ...

\mingb


\section{\kaib Jordan-Holder 定理}

Let $G$ be a finite group. If $G$ is not simple, then $G$ has a normal
subgroup $G_1\neq G$ such that $G/G_1$ is simple\textit{.} Just let $G_1$ be
a maximal normal subgroup in the finite group $G$\textit{.} Similarly, $G_1$
has a normal subgroup $G_2$ such that $G_1/G_2$ is simple. Thus we get a
descending chain 
\[
G=G_0\supset G_1\supset G_2\supset \cdots \supset G_n=\{e\} 
\]
such that $G_{i+1}$ is normal in $G_i$, and $G_i/G_{i+1}$ is simple. Now
suppose that 
\[
G=H_0\supset H_1\supset H_2\supset \ldots \supset H_m=\{e\} 
\]
is another such chain of subgroups. The Jordan-Holder Theorem asserts that $%
m=n$, and that there is a one-to-one correspondence between the factor
groups $G_i/G_{i+1}$ and $H_j/H_{j+1}$ such that corresponding factor groups
are isomorphic. We will prove this remarkable theorem, but first some
notation and terminology are needed. \textbf{The groups considered are not
necessarily finite.}


\begin{definition}
\ \, 設 $G$ 為一群。 $G$ 的一正規級數就是一如下之群的鍊鎖:
\[
G=G_0\supset G_1\supset G_2\supset \ldots \supset G_n=\{e\}
\]
其中，對於每一 $i$,\ $\,$ $G_{i+1}$ 皆為 $G_i$ 之正規子群。
The groups $G_i/G_{i+1}$ are the factor groups of the chain.
The length of the chain is
the number of strict inclusions in the chain. A normal series is a
composition series if each factor group $G_i/G_{i+1}$ is a simple group $%
\neq \{e\}$. Two normal series are equivalent if there is a one-to-one
correspondence between their factor groups such that corresponding factor
groups are isomorphic.
\end{definition}



\begin{theorem}[Jordan-Holder]
\ \, Any two composition series of a group are equivalent.
\end{theorem}


\proof\ \ If a group has a composition series of length
one, then the group is simple and any two composition series are certainly
equivalent. Now suppose that a group $G$ has a composition series



\begin{equation}  \label{one}
G=G_0\supset G_1\supset G_2\supset \ldots \supset G_n=\{e\}
\end{equation}


of length $n>1$, and that if a group has a composition series of length less
than $n$, then any two composition series of that group are equivalent. Let


\begin{equation}  \label{two}
G=H_0\supset H_1\supset H_2\supset \ldots \supset H_m=\{e\}
\end{equation}
be any composition series of $G$. Consider the series


\begin{equation}  \label{three}
G=G_0\supset G_1\supset G_1\cap H_1\supset G_2\cap H_1\supset \ldots \supset
G_n\cap H_1=\{e\}
\end{equation}
and

\begin{equation}  \label{four}
G=H_0\supset H_1\supset H_1\cap G_1\supset H_2\cap G_1\supset \ldots \supset
H_m\cap G_1=\{e\}
\end{equation}
Since $G_{i+1}\cap H_1$ is a normal subgroup of $G_i\cap H_1$ and $%
G_i\supset G_{i+1}$, the Third Isomorphism Theorem (\textbf{2.3.12}) yields 
\[
(G_i\cap H_1)/(G_{i+1}\cap H_1)=(G_i\cap H_1)/(G_{i+1}\cap (G_i\cap
H_1))\approx 
\]
\[
G_{i+1}(G_i\cap H_1)/G_{i+1}, 
\]
and $G_{i+1}(G_i\cap H_1)$ is a normal subgroup of $G_i$ since it is a
product of two normal subgroups. Since $G_i/G_{i+1}$ is a simple group, $%
(G_{i+1}(G_i\cap H_1))/G_{i+1}$ is either $G_i/G_{i+1}$ or $G_{i+1}/G_{i+1}$%
. That is, $G_{i+1}(G_i\cap H_1)$ is either $G_{i+1}$ or $G_i$. Therefore,
if we remove repetitions from 
\[
G_1\supset (G_1\cap H_1)\supset (G_2\cap H_1)\supset \ldots \supset (G_n\cap
H_1)=\{e\}, 
\]
we get a composition series for $G_1$. By our induction hypothesis, the
resulting composition series is equivalent to the composition series 
\[
G_1\supset G_2\supset \ldots \supset G_n=\{e\}\text{,} 
\]
and hence (\ref{one}) and (\ref{three}) (with repetitions removed) are
equivalent. $\cdots$



%\end{document}
\section{問 題 集 Problem set}



\begin{enumerate}
\item 試証: 若 $G$ 有一合成級數，則任何正規子群 $G$ 都有合成級數。

\item  試証: 若 $N$  在 $G$ 中為正規，且若 $G$ 有一合成級數，則 $G/N$ 亦然。

\item  Suppose that $G$ has a composition series and that $N$ is normal in $%
G $. Prove that $G$ has a composition series of which $N$ is a member.

\item  Suppose that $G$ has a composition series. Prove that any normal
series of $G$ has a refinement that is a composition series.

\item  \label{zasslemma}(\textbf{Zassenhaus's Lemma}) Let \textit{A} and $B$
be subgroups of a group $G$, and let $M$ and $N$ be normal in \textit{A} and 
$B$, respectively. Prove that
\end{enumerate}


\chapter{其 他}
\section{圖形與表格}

\begin{figure}[htb]
  \setlength{\unitlength}{0.1mm}   \begin{center}
    \begin{picture}(181,181)(0,0)
      \thinlines \multiput(80,80)(-20,-20){4}{\framebox(80,80){}}
      \thicklines \put(0,0){\framebox(180,180){}} 
      \put(60,60){\line( 1, 1){ 60}}
    \end{picture}
  \end{center}
 \caption[原始之圖]{原始之圖 Primitive figure.}
\end{figure}


{
\renewcommand{\footnoterule}{}
\begin{table}[hbp]
\footnotesize
\vglue0pt
\caption{出版工具 Comparison of Publishing Tools}
\begin{center}
 \renewcommand{\footnoterule}{}
 \begin{center}
 \renewcommand{\thefootnote}{\fnsym{footnote}}

\begin{tabular}{crr} \thickhline
Tool & \multicolumn{1}{c}{Learning Curve %\footnote{1.0 being easiest} 
}& \multicolumn{1}{c}{Support             %\footnote{10.0 being the best}
}\\ \thinhline 
FrameMaker & 5.0 & 6.0 \\  
Troff & 10.0 & 1.0 \\
\TeX                                     %\footnote{\TeX\ is the winner!}\/ 
& 7.0 & 10.0  \\ \thickhline
\end{tabular}
\linethickness{0pt}
\end{center}
\end{center}
\end{table}
}








\begin{thebibliography}{9}
\bibitem[杜甫 1964]{dunford}  N. Dunford and J. Schwartz, 泛函分析,

\bibitem{} M. Struwe, \emph{Semilinear wave equations}, Bull. Amer. Math.
Soc. \textbf{26} (1992), 53-85.

\bibitem{} W.P. Thurston, \emph{Geometry and topology of three manifolds},
Lecture notes, Princeton Univ., NJ, 1979.

\end{thebibliography}


%\references

\appendix

\chapter{使 用 ChiTeX}



\begin{theindex}
 \item 代數 1, 12
 \item series 2, 33
   \subitem convergent, 22, 55
 \indexspace
\end{theindex}



\end{document}



