I've been attempting to typeset some predicate logic proofs in the style of Huth and Ryan, and I'm having trouble determining how to display declared variables in the same format. Below is an example of one of these proofs.
I've been using the logicproof
package to typeset my proofs so far, and this is what I have presently when recreating the above proof.
Does anyone have any insight as to how to declare the variable to the left of the statement?
LaTeX source:
\documentclass{article}
\usepackage{logicproof}
\begin{document}
\begin{logicproof}{1}
\forall x \, (P(x) \to Q(x)) & premise \\
\forall x \, P(x) & premise \\
\begin{subproof}
P(x_0) \to Q(x_0) & $\forall x \, \mathrm{e}$ 1 \\
P(x_0) & $\forall x \, \mathrm{e}$ 2 \\
Q(x_0) & $\to \mathrm{e}$ 3, 4
\end{subproof}
\forall x \, Q(x) & $\forall x \, \mathrm{i}$ 3--5
\end{logicproof}
\end{document}
\documentclass
, including all necessary packages, etc., ending with\end{document}
. It saves work for those wishing to help you, and provides additional [often necessary] information.natded
. This seems to have facilities somewhat closer to what is needed here, even though designed for (two) different ways of laying out proofs.