\begin{frame}
  \frametitle{Elimination of $\vee$}
  
  \begin{goal}{Elimination of $\vee$}
    \vspace{-1ex}
    \begin{align*}
      \infer[\rulename{\vee_e}]
      {\gamma}
      {
        \alpha \vee \beta && 
        \framebox{\parbox{.8cm}{\centerline{$\alpha$}\centerline{$\vdots$}\centerline{$\gamma$}}} &&
        \framebox{\parbox{.8cm}{\centerline{$\beta$}\centerline{$\vdots$}\centerline{$\gamma$}}} 
      }
    \end{align*}
  \end{goal}
\end{frame}