\begin{frame}
  \frametitle{Kripke Models: Labelling Function}
  
  \begin{goal}{}
    The \emph{labelling function} $\lab{L}$ tells which propositional letters
    are true in which world:
    \begin{talign}
      w \fc p  \;\iff\; p \in L(w)
    \end{talign}
  \end{goal}
  $L(w)$ are the propositional letters that are true in world $w$!
  \pause
  \medskip
  
  \begin{exampleblock}{}
    \begin{minipage}{.6\textwidth}
    \exampleA
    \end{minipage}
    \begin{minipage}{.39\textwidth}
    \begin{talign}
      \lab{L}(w_1) &= \{\; \lab{p} \;\} \\
      \lab{L}(w_2) &= \{\; \lab{q} \;\} \\
      \lab{L}(w_3) &= \{\; \lab{p,\; r} \;\}
    \end{talign}
    \end{minipage}
    \pause\vspace{3ex}
    
    Hence
    \begin{talign}
    w_1  &\fc \lab{p} &
    w_2  &\fc \lab{q} &
    w_3  &\fc \lab{p} &
    w_3  &\fc \lab{r} &
    \mpause[1]{w_3  &\notfc \lab{q}}
    \end{talign}
  \end{exampleblock}
\end{frame}