\begin{frame}{Models in Predicate Logic with Equality}
\begin{block}{}
\emph{Truth} of a formula $\formula{\aform}$ in a model $\model{\amodel}$ with universe $\model{\adomain}$
{\it with respect to environment $\saluf$}
is defined by induction on the structure of $\formula{\aform}$:
\medskip
Atomic formulas:
\begin{itemize}\setlength{\itemsep}{0.4ex}
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\narypredsynvar{P}{\ateri{1},\ldots,\ateri{n}}}
\;\iff\; \tuple{\interpretin{\formula{\ateri{1}}}{\model{\amodel},\saluf},
\ldots,
\interpretin{\formula{\ateri{n}}}{\model{\amodel},\saluf}}
\in \interpretin{\snarypredsynvar{P}}{\model{\amodel}} $
\mpause[1]{
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\equalto{\ateri{1}}{\ateri{2}}}
\iff
\pair{ \intin{\formula{\ateri{1}}}{\model{\amodel},\saluf} }{ \intin{\formula{\ateri{2}}}{\model{\amodel},\saluf} }
\in {\intin{\sequalto}{\model{\amodel}}}
\iff
\intin{\formula{\ateri{1}}}{\model{\amodel},\saluf} = \intin{\formula{\ateri{2}}}{\model{\amodel},\saluf}$
}
\end{itemize}
\smallskip
Logic connectives:
\begin{itemize}\setlength{\itemsep}{0.4ex}
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\lognot{\aform}}
\;\iff\; \model{\amodel} \satisfiesnotlookup{\saluf} \formula{\aform}$
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\logand{\aform}{\bform}}
\;\iff\; \model{\amodel} \satisfieslookup{\saluf} \formula{\aform}
\;\text{ and }\;
\model{\amodel} \satisfieslookup{\saluf} \formula{\bform}$
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\logor{\aform}{\bform}}
\;\iff\; \model{\amodel} \satisfieslookup{\saluf} \formula{\aform}
\;\text{ or }\;
\model{\amodel} \satisfieslookup{\saluf} \formula{\bform}$
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\logimp{\aform}{\bform}}
\;\iff\; (\text{if }\; \model{\amodel} \satisfieslookup{\saluf} \formula{\aform}
\;\text{ then }\; \model{\amodel} \satisfieslookup{\saluf} \formula{\bform} )$
\end{itemize}
\smallskip
Quantifiers:
\begin{itemize}\setlength{\itemsep}{0.4ex}
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\forallst{x}{\,\aform}}
\;\iff\; \text{for all $\forestgreen{a} \in \model{\adomain}$ it holds: }
\model{\amodel} \satisfieslookup{\saluf\alert{[x\mapsto \forestgreen{a}]}} \formula{\aform}$
\item
$\model{\amodel} \satisfieslookup{\saluf} \formula{\existsst{x}{\,\aform}}
\;\iff\; \text{for some $\forestgreen{a} \in \model{\adomain}$ it holds: }
\model{\amodel} \satisfieslookup{\saluf\alert{[x\mapsto \forestgreen{a}]}} \formula{\aform} $
\end{itemize}
\end{block}
\end{frame}