答案1
像这样吗?
\documentclass{article} % or some other suitable document class
\usepackage{amsthm} % for 'proof' environment
\usepackage{enumitem} % sophisticated controls for list-like environments
\usepackage{lipsum} % filler text
\usepackage{newtx} % optional (Times Roman text and math font clone)
\begin{document}
\begin{proof} \mbox{}
\begin{itemize}[itemindent = 0pt,leftmargin = 2\parindent]
\item[$1\Rightarrow 2$] \lipsum[1][1-4]
\item[$2\Rightarrow 3$] \lipsum[2][1-3]
\item[$3\Rightarrow 1$] \lipsum[3][1-4]
\end{itemize}
\end{proof}
\end{document}
答案2
你可以做到,但这真的有吸引力吗?对我来说没有。无论如何,我给你一个比较:下面你会看到我会怎么做。
我希望你不打算在这样的证明里放列表。别忘了\qedhere
在结尾处alignedproof
。
\documentclass{article}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{enumitem}
\usepackage{lipsum}
\newtheorem{proposition}{Proposition}
\newlength{\alignedproofindent}
\NewDocumentEnvironment{alignedproof}{O{\proofname}m}
{%
\proof[#1]\mbox{}\par\nopagebreak
\settowidth{\alignedproofindent}{#2\quad}%
\everypar{\hangindent=\alignedproofindent\hangafter=0 }%
}
{\endproof}
\NewDocumentCommand{\alignedproofstep}{m}{%
\par\noindent\makebox[0pt][r]{%
\makebox[\alignedproofindent][l]{#1}%
}\ignorespaces
}
\newcommand{\gives}{${{}\Rightarrow{}}$}
\begin{document}
\begin{proposition}
\lipsum[1][1-3]
\end{proposition}
\begin{alignedproof}{1\gives2}
\alignedproofstep{1\gives2}
\lipsum[2][1-4]
\lipsum[2][5-8]
\alignedproofstep{2\gives3}
\lipsum[3][1-2]
\alignedproofstep{3\gives1}
\lipsum*[4][1-2]\qedhere
\end{alignedproof}
\begin{proof}
(1\gives2)
\lipsum[2][1-4]
\lipsum[2][5-8]
(2\gives3)
\lipsum[3][1-2]
(3\gives1)
\lipsum*[4][1-2]
\end{proof}
\end{document}