# TikZ and subfigures in math nodes

Yep, it is possible to revert back but to just supset, but don't see the harm in just using Supset. It just feels "wrong" to use a math symbol like that without a $..$ surrounding it, even though it appears that the symbols and text are in proper math font. Don't know if there are other workarounds, and I certainly would not want to use \pgfmatrixnextcell, but perhaps one of the TikZ experts here will elaborate. –  Peter Grill Sep 28 '11 at 20:42

Another option is to consider the subcaption package. This post has some good comparisons: subcaption vs. subfig

Below is an implementation using the subcaption package, and I didn't need to change your TikZ code at all :)

\documentclass{article}
\usepackage{tikz}% http://ctan.org/pkg/pgf
\usetikzlibrary{matrix}
\usepackage{subcaption}

\begin{document}
\begin{figure}
\centering
\begin{subfigure}{0.5\textwidth}
\begin{tikzpicture}[every node/.style={anchor=west}]
\matrix (m) [matrix of math nodes, nodes in empty cells]{
\quad & 1.\quad (x)(Q\supset Fx) & \\
& 2.\quad Q\supset Fx & \textrm{I,\textbf{UI}} & \\
& 3.\quad Q \\
& 4.\quad Fx & 2, 3, \textrm{ M.P.}\\
& 5.\quad (x)Fx & 4, \textrm{ \textbf{UG}} \\
& 6.\quad Q\supset(x)Fx & 3-5, \textrm{ C.P.} \\
$(x)(Q\supset(x)Fx)\supset$\\
$[Q\supset(x)Fx]$} & 1-6, \textrm{ C.P.}\\};
\draw[-stealth] (m-7-2.north east)
-| (m-1-1.west) |- (m-1-2);
\draw[-stealth] (m-6-2.north east)
-| (m-3-1.east) |- (m-3-2);
\end{tikzpicture}%
\caption{Subcaption goes here}
\end{subfigure}
\caption{This is a caption}
\end{figure}
\end{document}


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