使用 amsthm 的定理环境后没有缩进

Question

我使用 amsthm 包，并且不希望定理环境之后的行缩进。我查阅了包的手册，它说要定义一种新的定理样式。我希望以下 MWE 能够完成这项任务。

\documentclass[12pt,a4paper]{scrreprt}

\usepackage{amsthm}
\newtheoremstyle{abcd}% name
  {}%      Space above, empty = `usual value'
  {}%      Space below
  {\itshape}% Body font
  {}%         Indent amount (empty = no indent, \parindent = para indent)
  {\bfseries}% Thm head font
  {.}%        Punctuation after thm head
  {.5em}% Space after thm head: \newline = linebreak
  {}%         Thm head spec
\theoremstyle{abcd}

\newtheorem{defn}{Definition}
\begin{document}
\begin{defn}
Some defintion
\end{defn}
This sentence shouldn't be indented.
\end{document}

然而，我最终得到了这个

这正是我所期望的（在定理环境结束后立即使用 noindent 获得）

Answer 1

\documentclass[12pt,a4paper]{scrreprt}
\usepackage{amsthm}
\usepackage{etoolbox}

\newtheorem{defn}{Definition}
\AfterEndEnvironment{defn}{\noindent\ignorespaces}

\begin{document}
\begin{defn}
Some definition.
\end{defn}
This sentence isn't indented.
\end{document}

然而，这违背直觉；定义（或任何其他类似定理的结构）之后的句子在逻辑上开始一个新段落，因此其第一行应被视为新段落的任何其他第一行。

Answer 2

您可以通过修补在单个定理类型的基础上修复此问题\end<name>：

\documentclass{article}

\usepackage{etoolbox}
\usepackage{amsthm}

\newtheoremstyle{abcd}% name
  {}%      Space above, empty = `usual value'
  {}%      Space below
  {\itshape}% Body font
  {}%         Indent amount (empty = no indent, \parindent = para indent)
  {\bfseries}% Thm head font
  {.}%        Punctuation after thm head
  {.5em}% Space after thm head: \newline = linebreak
  {}%         Thm head spec

\theoremstyle{abcd}
\newtheorem{defn}{Definition}

\makeatletter
\patchcmd{\enddefn}{\@endpefalse}{}{}{}
\makeatother


\begin{document}

\begin{defn}
Some definition
\end{defn}
This sentence shouldn't be indented.

\begin{defn}
Some definition
\end{defn}

This sentence should be indented.

\end{document}

风格选择没有影响。

为了获得相同的行为全部定理环境，改变的定义\@endtheorem。

\documentclass{article}

\usepackage{amsthm}

\makeatletter
\def\@endtheorem{\endtrivlist}
\makeatother

\newtheoremstyle{abcd}% name
  {}%      Space above, empty = `usual value'
  {}%      Space below
  {\itshape}% Body font
  {}%         Indent amount (empty = no indent, \parindent = para indent)
  {\bfseries}% Thm head font
  {.}%        Punctuation after thm head
  {.5em}% Space after thm head: \newline = linebreak
  {}%         Thm head spec

\theoremstyle{abcd}
\newtheorem{defn}{Definition}

\begin{document}

\begin{defn}
Some definition
\end{defn}
This sentence shouldn't be indented.

\begin{defn}
Some definition
\end{defn}

This sentence should be indented.

\end{document}

另一个例子，表明当两个定理环境相互衔接时不会增加不必要的空间。

\documentclass{scrbook}

\usepackage{amsthm}
\makeatletter
\def\@endtheorem{\endtrivlist}
\makeatother

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[chapter]
\newtheorem*{thm*}{Theorem}

\begin{document}

\chapter{Chapter}

\section{Section}

Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 

\begin{thm}
    Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. 
\end{thm}
No indentation. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 

\begin{thm}
    Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. 
\end{thm}

\begin{thm}
    Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. Theorem. 
\end{thm}

Indentation. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 

\end{document}