如何从校样、定义和备注环境中删除斜体字母？

Question

我有以下文件：

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\newtheorem{thm}{Theorem}[section]
\newtheorem{cor}[thm]{Corollary}
\newtheorem{lem}[thm]{Lemma}
\newtheorem{prop}[thm]{Proposition}
\newtheorem{defn}[thm]{Definition}
\newtheorem{rem}[thm]{Remark}
\newtheorem{proof}{Proof}
\numberwithin{equation}{section}
\begin{document}
\section{Section 1}
\begin{thm}
Theorem.
\end{thm}
\begin{rem}
Remark.
\end{rem}
\begin{lem}
Lemma
\end{lem}
\begin{prop}
Proposition.
\end{prop}
\begin{cor}
Corollary.
\end{cor}
\begin{defn}
Definition.
\end{defn}
\begin{thm}
Theorem.
\end{thm}
\begin{proof}
Proof.
\end{proof}
\end{document}

其规定如下：

如何\textit从证明内容（在我的例子中是：这里的一些证明）中删除定义和备注？我尝试更改命令，\newtheorem但没有成功。

Answer 1

只需加载amsthm并用于\theoremstyle{definition}您不想要斜体的环境即可。

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amsthm}

\newtheorem{thm}{Theorem}[section]
\newtheorem{cor}[thm]{Corollary}
\newtheorem{lem}[thm]{Lemma}
\newtheorem{prop}[thm]{Proposition}

\theoremstyle{definition}
\newtheorem{defn}[thm]{Definition}
\newtheorem{rem}[thm]{Remark}
%\newtheorem{proof}{Proof}

\numberwithin{equation}{section}

\begin{document}
\section{Section 1}
\begin{thm}
Theorem.
\end{thm}
\begin{rem}
Remark.
\end{rem}
\begin{lem}
Lemma
\end{lem}
\begin{prop}
Proposition.
\end{prop}
\begin{cor}
Corollary.
\end{cor}
\begin{defn}
Definition.
\end{defn}
\begin{thm}
Theorem.
\end{thm}
\begin{proof}
Proof.
\end{proof}
\end{document}

Answer 2

（在意识到 OP 只想更改少数（但不是全部）类定理环境的正文字体后，我修改了我的答案。）

我建议你加载定理\theorembodyfont{\upshape}打包并在 之前发出指令\newtheorem{defn}[thm]{Definition}。这样，只有最后三个\newtheorem声明会受到字体更改的影响。

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb} % 'amssymb' loads 'amsfonts' automatically

\usepackage{ntheorem} % for '\theorembodyfont' macro

\newtheorem{thm}{Theorem}[section]
\newtheorem{cor}[thm]{Corollary}
\newtheorem{lem}[thm]{Lemma}
\newtheorem{prop}[thm]{Proposition}

\theorembodyfont{\upshape}
\newtheorem{defn}[thm]{Definition}
\newtheorem{rem}[thm]{Remark}
\newtheorem{proof}{Proof}


\begin{document}

\section{Introduction}

\begin{thm}   Theorem. \end{thm}
\begin{rem}   Remark.  \end{rem}
\begin{lem}   Lemma.   \end{lem}
\begin{prop}  Proposition. \end{prop}
\begin{cor}   Corollary.   \end{cor}
\begin{defn}  Definition.  \end{defn}
\begin{thm}   Theorem. \end{thm}
\begin{proof} Proof.   \end{proof}

\end{document}