\begin{frame}
  \frametitle{Examples: Semantics Intuitive}

  \begin{exampleblock}{}
    Assume that
    \begin{itemize}
      \item $R(x,y)$ means `$x$ knows $y$'.
    \end{itemize}
    \pause\medskip
    
    What is then the intuitive meaning of the following formulas?
    \begin{itemize}
    \pause
      \item $\myall{x}{\myex{y}{R(x,y)}}$
        \pause \\
        \hint{Everybody knows somebody.}
        \medskip
    \pause
      \item $\myex{y}{\myall{x}{R(x,y)}}$
        \pause \\
        \hint{Somebody is known by everybody.}
        \medskip
    \pause
      \item $\myall{y}{\myex{x}{R(x,y)}}$
        \pause \\
        \hint{Everybody is known by somebody.}
        \medskip
    \pause
      \item $\myex{x}{\myall{y}{R(x,y)}}$
        \pause \\
        \hint{Somebody knows everybody.}
        \medskip
    \end{itemize}
  \end{exampleblock}
  \pause
  \begin{alertgoal}{}
    For the exam you need to be able to interpret formulas!
  \end{alertgoal}
\end{frame}