\item \self Consider a formula $\varphi$ in propositional logic. In the
    following list, tick all statements that are true.

\begin{itemize}
\item[$\square$] If $\varphi$ is a tautology, a falsifying model can be found.
\item[$\ticked$] If $\varphi$ is equivalent to $\psi$, a satisfying model for $\varphi$ always satisfies $\psi$.
\item[$\square$] If $\varphi$ has no satisfying model, it is called a tautology.
\item[$\square$] If $\varphi$ semantically entails $\psi$, a satisfying model for $\psi$ always satisfies $\varphi$.

\end{itemize}
