\begin{frame}{Exercises (1)}
%   (Groups of two, 1 minute)  
  \begin{exampleblock}{}
    \emph{Show that the following language is context-free:}
    \begin{talign}
      \{\, a^n\, b^m\, c^{2n} \mid n\geq 0,\; m\ge 0 \,\}
    \end{talign}
    \pause
    We give a context-free grammar for the language:
    \pause
    \begin{align*}
      S &\to aScc \mpause[1]{\mid T} \\
      \mpause{T &\to bT \mid \lambda}
    \end{align*}
    The start variable is $S$.
  \end{exampleblock}
  
%   (Groups of two, 1 minute)  
\end{frame}