LaTeX.org

I've seen some solutions on creating an bracket over an array environment, but in fact they do not work well. I have a formula figure like this:
/begin{figure}
\[
\begin(array}{ll}
\prooftree
\begin{array}{c}
....FORMULA A....
\end{array}
\justifies
...FORMULA B...
\endprooftree
\]
/end{figure ...