\begin{enumerate}
    \item $a:$ \quad Alice is going to the conference. \\
          $b:$ \quad Bob is going to the conference.
          $$ a \land b \lor \neg a \land \neg b$$
    \item $S:$ \quad Mozart was born in Salzburg. \\
          $I:$ \quad Mozart was born in Innsbruck
          $$ S \land \neg I $$
    \item $m:$ \quad A model assigns truth values to variables of a propositional formula.
          $$ m $$
\end{enumerate}