\begin{frame}{Exercise}
  \begin{exampleblock}{Question}
    \emph{Is the following language regular?}
    \begin{talign}
      \{\,a^n b^n \mid n \geq 0 \,\}
    \end{talign}
    \pause
    \alert{This language is not regular!}
    \pause\medskip
    
    \emph{Intuition:}
    a DFA has only a finite memory (the states).
  \end{exampleblock}
  We will later prove this using the \emph{pumping lemma}.  

%   \begin{exampleblock}{}
%     Give a deterministic automaton with \emph{infinitely} many states for
%     \begin{align*}
%       \{\, a^n b^n \mid n \geq 0 \,\}
%     \end{align*}
%     \pause
%     Answer in the lecture.
%   \end{exampleblock}
%   \pause\medskip
\end{frame}