\begin{frame}{Proving Semantic Entailment} \begin{exampleblock} {\begin{center} \black{% $\satstmt{% \formula{\lognot{\forallst{x}{\,\unpred{P}{x}}}} \satisfies \formula{\existsst{x}{\,\lognot{\unpred{P}{x}}}}}$} \end{center}}\pause{} \medskip For all models $\model{\amodel}$ with domain $\model{\adomain}$ and environments $\saluf$ we find:\pause{} \begin{align*} & \model{\amodel} \satisfieslookup{\saluf} \formula{\lognot{\forallst{x}{\,\unpred{P}{x}}}} \\ & \uncover<4->{% \hspace*{2ex} \;\;\Longleftrightarrow\;\; \text{not:} \;\; \model{\amodel} \satisfieslookup{\saluf} \formula{\forallst{x}{\,\unpred{P}{x}}}} \\ & \uncover<5->{% \hspace*{2ex} \;\;\Longleftrightarrow\;\; \text{not for all $\forestgreen{a}\in\model{\adomain}\,$:} \;\; \model{\amodel} \satisfieslookup{\saluf[\freevar{x}\mapsto \forestgreen{a}]} \formula{\unpred{P}{\freevar{x}}}} \\ & \uncover<6->{% \hspace*{2ex} \;\;\Longleftrightarrow\;\; \text{there exists $\forestgreen{a}\in\model{\adomain}$ such that not:} \;\; \model{\amodel} \satisfieslookup{\saluf[\freevar{x}\mapsto \forestgreen{a}]} \formula{\unpred{P}{\freevar{x}}}} \\ & \uncover<7->{% \hspace*{2ex} \;\;\Longleftrightarrow\;\; \text{there exists $\forestgreen{a}\in\model{\adomain}$ such that:} \;\; \model{\amodel} \satisfiesnotlookup{\saluf[\freevar{x}\mapsto \forestgreen{a}]} \formula{\unpred{P}{\freevar{x}}}} \\ & \uncover<8->{% \hspace*{2ex} \;\;\Longleftrightarrow\;\; \text{there exists $\forestgreen{a}\in\model{\adomain}$ such that:} \;\; \model{\amodel} \satisfieslookup{\saluf[\freevar{x}\mapsto \forestgreen{a}]} \formula{\lognot{\unpred{P}{\freevar{x}}}}} \\ & \uncover<9->{% \hspace*{2ex} \;\;\Longleftrightarrow\;\; \model{\amodel} \satisfieslookup{\saluf} \formula{\existsst{x}{\,\lognot{\unpred{P}{x}}}}} \end{align*} \uncover<10->{% Hence we can conclude: $\satstmt{% \formula{\lognot{\forallst{x}{\,\unpred{P}{x}}}} \satisfies \formula{\existsst{x}{\,\lognot{\unpred{P}{x}}}}}$.} \end{exampleblock} \end{frame}