%%% Theorems
\theoremstyle{plain}
\newtheorem{theorem}{定理}
\newtheorem{proposition}{命题}
\newtheorem{lemma}{引理}
\newtheorem{claim}{断言}
\newtheorem{corollary}{系}
\theoremstyle{definition}
\newtheorem{definition}{定义}
\newtheorem{example}{例}
\newtheorem{remark}{注}
\theoremstyle{remark}
\newtheorem{situation}{}
\newtheorem{exercise}{}
%\renewcommand*{\theexercise}{\thesection-\Alph{exercise}}
\renewcommand{\qedsymbol}{$\blacksquare$}
% \newcommand{\footnote}[1]{\textcolor{0xcccccc}{（#1）}}
\newcommand{\textsf}[1]{\textbf{#1}}
\newcommand{\intervalopen}[2]{\left]{#1},{#2}\right[}
\newcounter{image}
\def\image#1#2#3{%
{{image|#1|#2|center|#3}}%
\refstepcounter{image}%
\begin{center}图 \arabic{image}: #3\end{center}
}
%\def\emph#1{\underline{#1}}
\renewenvironment{itemize}{\begin{enumerate}[label=$\diamond$]}{\end{enumerate}}