答案1
该amsthm
包提供了三种预定义的定理样式:theorem
、definition
和remark
。该指令\theoremstyle{rem}
应该会抛出一条警告消息——你注意到了吗?
\theoremstyle{remark}
如果您想要remark
称为 的环境的样式,则使用,或者对和环境都rem
使用定理样式。definition
defn
rem
\documentclass[11pt,openany]{book}
\usepackage{amsmath,amssymb,amsthm}
\newtheorem{teo}{Theorem}[section]
\theoremstyle{definition} % optional
\newtheorem{defn}[teo]{Definition}
\theoremstyle{remark}
\newtheorem{rem}[teo]{Remark}
\begin{document}
\setcounter{chapter}{2} % just for this example
\setcounter{section}{1}
\begin{defn}[$\sigma$-algebras]
Let $\Omega$ be a non-empty set. \dots
\end{defn}
\begin{rem}
If $\{A_i\}_{i=1}^{\infty}\subset\mathcal{F}$, \dots
\end{rem}
\begin{defn}[Measures and Measurability]
Let $\Omega\neq\emptyset$ and \dots
\end{defn}
\end{document}