\item \ifassignmentsheet \points{5} \fi
  Use the lazy encoding approach to check whether the formula $\varphi$ in $\EUF$ is satisfiable.
\begin{align*}
  \varphi =&(\clause{(f(x)=x); (f(x)=y); (x=y)}) \land (\clause{\lnot (f(x)=x); (f(x)=y)})~\land \\
           &(\clause{\lnot (f(x)=y); (x=y)}) \land (\clause{(x=y); (z=f(x))})~\land \\
           &(\clause{\lnot (x=y); (f(x)=y)}) \land (\clause{\lnot (z=f(x)); \lnot (f(x)=y)})
\end{align*}