<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">\documentclass[convert={outfile=\jobname.svg}]{standalone}

\usepackage{proof}
\usepackage{amsmath}
\usepackage{utf8}

\begin{document}

$$
\infer[absurd]{Â¬(Pâˆ§Q),P,Q âŠ¢ Â¬Pâˆ¨Â¬Q}{
  \infer[âˆ§~intro]{\cdots âŠ¢ Pâˆ§Q}{
    \infer[assum]{\cdots,P âŠ¢ P}{}
    &amp;
    \infer[assum]{\cdots,Q âŠ¢ Q}{}
  }
  &amp;
  \infer[assum]{\cdots, Â¬(Pâˆ§Q) âŠ¢ Â¬(Pâˆ§Q)}{}
}
$$
\end{document}
</pre></body></html>