\item Considering formulas $\varphi$ and $\psi$ regarding a theory $\Theory$.
\begin{itemize}
    \item When is a formula $\varphi$ $\mathcal{T}$-valid?
    \item When is a formula $\varphi$ $\mathcal{T}$-satisfiable?
    \item When does $\varphi$ $\mathcal{T}$-entail $\psi$?
\end{itemize}
