如何使用 busproofs 调整证明树？

Question

我曾经bussproofs.sty创建过这个自然演绎规则：

来源：

\documentclass{beamer}

\usepackage{bussproofs}

\begin{document}

\begin{frame}

    \AxiomC{$A\vee B$}
    \AxiomC{[$A$]}
      %\vspace{-2em}
      \noLine
      \UnaryInfC{\vdots}
      \noLine
      \UnaryInfC{$C$} 
    \AxiomC{[$B$]}
      \noLine
      \UnaryInfC{$\vdots$}
      \noLine
      \UnaryInfC{$C$}
    \RightLabel{$\vee$E}
    \TrinaryInfC{$C$}
    \DisplayProof 

\end{frame}

\end{document}

如何才能使假设和垂直点之间的距离更小？我尝试\vspace使用负距离，但它在另一个块上起作用。

Answer 1

您可以粉碎它们\vdots并赋予它们与大写字母相同的高度。

\documentclass{beamer}

\usepackage{bussproofs}

\newcommand{\svdots}{\vphantom{\ensuremath{X}}\smash{\vdots}}

\begin{document}

\begin{frame}

    \AxiomC{$A\vee B$}
    \AxiomC{[$A$]}
      \noLine
      \UnaryInfC{\svdots}
      \noLine
      \UnaryInfC{$C$}
    \AxiomC{[$B$]}
      \noLine
      \UnaryInfC{\svdots}
      \noLine
      \UnaryInfC{$C$}
    \RightLabel{$\vee$E}
    \TrinaryInfC{$C$}
    \DisplayProof

\end{frame}

\end{document}

Answer 2

使用纯 TeX 有帮助：

\documentclass{beamer}

\usepackage{bussproofs}

\begin{document}

\begin{frame}

    \AxiomC{$A\vee B$}
    \AxiomC{[$A$]}
      %\vspace{-2em}
      \def\extraVskip{-2pt}
      \noLine
      \UnaryInfC{\vdots}
      \def\extraVskip{2pt}
      \noLine
      \UnaryInfC{$C$} 
    \AxiomC{[$B$]}
      \def\extraVskip{-2pt}
      \noLine
      \UnaryInfC{$\vdots$}
      \def\extraVskip{2pt}
      \noLine
      \UnaryInfC{$C$}
    \RightLabel{$\vee$E}
    \TrinaryInfC{$C$}
    \DisplayProof 

\end{frame}

\end{document}