\item \self Given two propositional logic formulas $\varphi$ and $\psi$.
Tick all statements that are true. 
\begin{enumerate}
	\item[$\square$] If $\phi \land \lnot \psi$ is not satisfiable, $\phi$ entails $\psi$.
	\item[$\square$] If $\lnot \phi$ is not valid, $\phi$ is satisfiable.
	\item[$\square$] If $\phi$ entails $\psi$ and $\psi$ entails $\phi$, both formulas are equivalent.
	\item[$\square$] If $\phi$ is equivalent to $\top$, $\phi$ is valid..
\end{enumerate}