定理的良好格式

Question

我正在写一篇包含一些定理的文章，我想对这些定理使用特殊的格式 - 我的想法是在定理的一侧放一条灰线。你能告诉我怎么做吗？

此外，如果您对定理等的良好格式有其他想法，我很乐意听听。

Answer 1

我有一个不同的问题，但也许答案来自马可·丹尼尔是您正在寻找的内容：不同颜色编码的定理. 他建议使用这个包mdframed。

我的论文的输出示例：

Answer 2

我最近请求一些关于定理修饰的帮助与定理环境一致的定理装饰。我想要一些能够与常规文本区分开的东西（以使定理脱颖而出），但不要太多。此外，环境应该很容易跨页面中断，而不会造成问题（带有孤立/寡妇装饰）或在视觉上“损坏”（如截断的框架）。经过一些修改后，结果如下：

\documentclass{article}
\usepackage{xcolor}% http://ctan.org/pkg/xcolor
\usepackage{ifmtarg}% http://ctan.org/pkg/ifmtarg
\usepackage{xifthen}% http://ctan.org/pkg/xifthen
\usepackage{environ}% http://ctan.org/pkg/environ
\usepackage{multido}% http://ctan.org/pkg/multido
\usepackage{lipsum}% http://ctan.org/pkg/lipsum

\makeatletter%
\newcommand{\theoremhang}{% top theorem decoration
  \begingroup%
  \setlength{\unitlength}{.005\linewidth}% \linewidth/200
    \begin{picture}(0,0)(1.5,0)%
      \linethickness{0.45pt} \color{black!50}%
      \put(-3,2){\line(1,0){206}}% Top line
      \multido{\iA=2+-1,\iB=50+-10}{5}{% Top hangs
        \color{black!\iB}%
        \put(-3,\iA){\line(0,-1){1}}% Top left hang
        \put(203,\iA){\line(0,-1){1}}% Top right hang
      }%
    \end{picture}%
  \endgroup%
}%
\newcommand{\theoremhung}{% bottom theorem decoration
  \nobreak
  \begingroup%
    \setlength{\unitlength}{.005\linewidth}% \linewidth/200
    \begin{picture}(0,0)(1.5,0)%
      \linethickness{0.45pt} \color{black!50}%
      \put(-3,0){\line(1,0){206}}% Bottom line
      \multido{\iA=0+1,\iB=50+-10}{5}{% Bottom hangs
        \color{black!\iB}%
        \put(-3,\iA){\line(0,1){1}}% Bottom left hang
        \put(203,\iA){\line(0,1){1}}% Bottom right hang
      }%
    \end{picture}%
  \endgroup%
}%

\newcounter{theorem}
\renewcommand{\thetheorem}{\arabic{theorem}}
\NewEnviron{theorem}[1][]{%
    \par\noindent\theoremhang\par\nobreak\noindent%\addvspace{-.5ex}
    \refstepcounter{theorem}\postdisplaypenalty=10000 %
    {\sffamily\bfseries\upshape Theorem \thetheorem\@ifnotmtarg{#1}{\ (#1)}}\ \ \itshape\ignorespaces%
    \BODY % Typeset theorem body/content
    \par\addvspace{-1ex}\nobreak\noindent\theoremhung\par\addvspace{.4ex}%
}
\makeatother

\begin{document}

\lipsum[1]

\begin{theorem}[Special theorem]
\lipsum[2]
\end{theorem}

And then there is also

\begin{theorem}[Short theorem]
This is just a short theorem description.
\end{theorem}

\lipsum[3]

\end{document}

Answer 3

不完全是你想要的，但这是一个例子唐纳德·阿瑟诺使用框架包：

\documentclass{article}
\usepackage{color,amsmath}
\usepackage{framed}
\makeatletter
\newdimen\errorsize \errorsize=0.2pt
% Frame with a label at top
\newcommand\LabFrame[2]{%
    \fboxrule=\FrameRule
    \fboxsep=-\errorsize
    \textcolor{FrameColor}{%
    \fbox{%
      \vbox{\nobreak
      \advance\FrameSep\errorsize
      \begingroup
        \advance\baselineskip\FrameSep
        \hrule height \baselineskip
        \nobreak
        \vskip-\baselineskip
      \endgroup
      \vskip 0.5\FrameSep
      \hbox{\hskip\FrameSep \strut
        \textcolor{TitleColor}{\textbf{#1}}}%
      \nobreak \nointerlineskip
      \vskip 1.3\FrameSep
      \hbox{\hskip\FrameSep
        {\normalcolor#2}%
        \hskip\FrameSep}%
      \vskip\FrameSep
    }}%
}}
\definecolor{FrameColor}{rgb}{0.25,0.25,1.0}
\definecolor{TitleColor}{rgb}{1.0,1.0,1.0}

\newenvironment{contlabelframe}[2][\Frame@Lab\ (cont.)]{% 
  % Optional continuation label defaults to the first label plus
  \def\Frame@Lab{#2}%
  \def\FrameCommand{\LabFrame{#2}}%
  \def\FirstFrameCommand{\LabFrame{#2}}%
  \def\MidFrameCommand{\LabFrame{#1}}%
  \def\LastFrameCommand{\LabFrame{#1}}%
  \MakeFramed{\advance\hsize-\width \FrameRestore} 
}{\endMakeFramed} 
\newcounter{theorem}
\newenvironment{theorem}[1]{%
  \par
  \refstepcounter{theorem}%
  \begin{contlabelframe}{Theorem \thetheorem:\quad #1}
 \noindent\ignorespaces}
{\end{contlabelframe}} 
\makeatother
\begin{document}
\begin{theorem}{Pythagoras}
This is a theorem
\end{theorem}
\end{document}

您将获得以下内容：

Answer 4

2011 年下半年，Thomas F. Sturm 发布了一个名为tcolorbox来创建您想要的特殊效果。这样，您就不需要像其他答案的示例那样在序言中创建如此大的开销。

这里我给你一个 MWE，但有关更多详细信息，请查看包装手册：

\documentclass{article}
\usepackage[listings]{tcolorbox}
\tcbuselibrary{listings,theorems}

\newtcbtheorem[number within=section]{mytheo}{My Theorem}%
{colback=green!5,colframe=green!35!black,fonttitle=\bfseries}{th}

\begin{document}

\begin{mytheo}{This is the theorem title}{label_of_the_theorem}
This is the text of the theorem. The counter is automatically assigned and,
in this example, prefixed with the section number. This theorem is numbered with
\ref{th:label_of_the_theorem} and is given on page \pageref{th:label_of_the_theorem}.
\end{mytheo}

The theorem enumerator adds the number of the section as indicated in the preamble.

\end{document}