答案1
看一下
http://www.logicmatters.net/latex-for-logicians/nd/
有一些软件包用于对此类序列进行 teXing。我猜你发布的序列是使用 proof.sty 完成的
答案2
由于其他答案只是一个链接,我想我会用该bussproofs
包来展示一个示例
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{bussproofs}
\newcommand{\implies}{\rightarrow}
\begin{document}
\begin{prooftree}
\AxiomC{Axiom}
\UnaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)], Q(a) \vdash Q(a)$}
\AxiomC{Axiom}
\UnaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)] \vdash P(a), Q(a)$}
\RightLabel{$[\neg \vdash]$}
\UnaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)], \neg P(a) \vdash Q(a)$}
\RightLabel{$[\lor \vdash]$}
\BinaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)], \neg P(a) \lor Q(a) \vdash Q(a)$}
\RightLabel{$[\implies \vdash r.w.]$}
\UnaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)], P(a) \implies Q(a) \vdash Q(a)$}
\RightLabel{$[\forall \vdash]$}
\UnaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)] \vdash Q(a)$}
\RightLabel{$[\vdash \forall]$}
\UnaryInfC{$\forall x [P(x)], \forall x [P(x) \implies Q(x)] \vdash \forall x [Q(x)$}
\end{prooftree}
\end{document}