如何将这个 ntheorem 解决方案移植到 amsthm + thmtools?

如何将这个 ntheorem 解决方案移植到 amsthm + thmtools?

是否可以重现此问题愉快的定理环境使用amsthmthmtools

答案1

您还可以使用包mdframed来绘制框架。 定理的设置可以用您最喜欢的包来完成。 设置定理环境后,您可以用 包围环境\surroundwithmdframed。 对于您需要的样式,您可以使用以下定义,其中短线的长度为 0.25 厘米。 当然,这可以做得更优雅。

为了简化代码,我使用了calcTikZ 库

\usepackage[framemethod=TikZ]{mdframed}
\usetikzlibrary{calc}
\makeatletter
\newrobustcmd*\mdf@tikzbox@tfl@spare[1]{%three or four borders
    \clip(0,0)rectangle(\mdfboundingboxwidth,\mdfboundingboxheight);%
    \begin{scope}[mdfcorners]%
       \clip[preaction=mdfouterline]%
            [postaction=mdfbackground]%
            [postaction=mdfinnerline]#1;%
    \end{scope}%
    \path[mdfmiddleline,mdfcorners]($(O|-P)-(0,0.25cm)$)--(O|-P)--(P)--($(P)-(0,0.25cm)$);
    \path[mdfmiddleline,mdfcorners]($(P|-O)+(0,0.25cm)$)--(P|-O)--(O)--($(O)+(0,0.25cm)$);
  }%
\newrobustcmd*\changelinestyle{\let\mdf@tikzbox@tfl\mdf@tikzbox@tfl@spare}
\makeatother
\surroundwithmdframed[settings=\changelinestyle]{theorem}

通过这个定义,所有的选项mdframed都是允许的。

在此处输入图片描述

\documentclass{article}
\usepackage{amsmath,amsthm}
\usepackage{thmtools}
\declaretheorem[]{theorem}

\usepackage[framemethod=TikZ]{mdframed}
\usetikzlibrary{calc}
\makeatletter
\newrobustcmd*\mdf@tikzbox@tfl@spare[1]{%three or four borders
    \clip(0,0)rectangle(\mdfboundingboxwidth,\mdfboundingboxheight);%
    \begin{scope}[mdfcorners]%
       \clip[preaction=mdfouterline]%
            [postaction=mdfbackground]%
            [postaction=mdfinnerline]#1;%
    \end{scope}%
    \path[mdfmiddleline,mdfcorners]($(O|-P)-(0,0.25cm)$)--(O|-P)--(P)--($(P)-(0,0.25cm)$);
    \path[mdfmiddleline,mdfcorners]($(P|-O)+(0,0.25cm)$)--(P|-O)--(O)--($(O)+(0,0.25cm)$);
  }%
\newrobustcmd*\changelinestyle{\let\mdf@tikzbox@tfl\mdf@tikzbox@tfl@spare}
\makeatother
\surroundwithmdframed[settings=\changelinestyle,middlelinecolor=blue,roundcorner=3pt,middlelinewidth=1.2pt]{theorem}

\usepackage{lipsum}
\begin{document}
\lipsum[2]

\begin{theorem}%
If~$G$ is a connected graph of order $n\geq 3$ and size~$m$, then
\[
    g(G)\geq \frac{m}{6}-\frac{n}{2}+1.%
\]
\end{theorem}%

\lipsum[2]

\end{document}

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