\begin{frame}{Encoding a PCP-Instance into a Formula} \begin{center} \scalebox{.8}{ \begin{minipage}{\textwidth} \understandmodel{} \end{minipage} } \end{center} \pause\smallskip \begin{goal}{} Interpreting $\aformi{2} \defdby \formula{\forallst{x}{\forallst{y}{ \bigl( \binpred{P}{x}{y} \logimpinf \bigwedge_{i=1,\ldots,k} \binpred{P}{\unfunci{f}{\forestgreen{w_i}}{x}}{\unfunci{f}{\forestgreen{v_i}}{y}} \bigr) }}}$: \pause\vspace{-.5ex} \begin{talign} & \amodel \satisfieslookup{\saluf} \aformi{2} \mpause[1]{ \;\;\Longleftrightarrow\;\; \ldots\\[-.25ex] & \Longleftrightarrow\;\; \Big( \text{$\forall w,v \in \model{{B}}\,$: $\pair{w}{v} \in \intin{\sbinpred{P}}{\amodel} \Longrightarrow \textstyle\bigwedge_{i=1,\ldots,k} \pair{\forestgreen{w_i}w}{\forestgreen{v_i}v} \in \intin{\sbinpred{P}}{\amodel}$} \Big) } \\[-.25ex] \mpause{ & \Longleftrightarrow\;\; \Big( \begin{aligned}[t] & \pair{\forestgreen{w}_{i_1}\cdots \forestgreen{w}_{i_n}} {\forestgreen{v}_{i_1}\cdots \forestgreen{v}_{i_n}} \in\intin{\sbinpred{P}}{\amodel} \\[-1ex] &\quad\Longrightarrow \pair{\forestgreen{w_i}\forestgreen{w}_{i_1}\cdots \forestgreen{w}_{i_n}} {\forestgreen{v_i}\forestgreen{v}_{i_1}\cdots \forestgreen{v}_{i_n}} \in\intin{\sbinpred{P}}{\model{\amodeli{\!\forestgreen{I}}}} \;\;\Big) \mpause{ \hspace*{1.5ex}\alert{\checkmark} } \end{aligned} } \end{talign} \end{goal} \vspace{10cm} \end{frame}