
\begin{logicproof}{1}
  p \land r 	& \prem\\
  p & $\ande{1} 1$ \\
  r & $\ande{2} 1$ \\
  \begin{subproof}
  s & \assum\\
  r & $\copying 2$
  \end{subproof}
  s \imp r & $\impi 4-5$\\
  \begin{subproof}
  q & \assum\\
  p & $\copying 1$
  \end{subproof}
  q \imp p & $\impi 7-8$ \\
  (q \imp p) \land (s \imp r) & $\andi 6,9$
\end{logicproof}
