\item \self Look at the following statements and tick them if they are true.

\begin{itemize}
\item[$\square$] Any sequent that is a correct semantic entailment can be proven.
\item[$\square$] Any sequent that can be proven is a correct semantic entailment.
\item[$\square$] If a sequent is not provable, the  semantic entailment relation does hold.
\item[$\square$] If for a sequent the semantic entailment relation does not hold, it cannot be proven with natural deduction.

\end{itemize}