Addition of a comment about declartive specification

Lectures/L15_MIS/MIS.tex

@@ -561,6 +561,12 @@ are isolated to their own access programs (like submodules). %    This, combined
 \item Algebraic specification
 \end{itemize}
 \item Best to follow a template
+\item Aim for \textbf{declarative} specification
+\begin{itemize}
+  \item Say what service is provided, but not how to provide it
+  \item Simpler
+  \item Allows for change in implementation
+\end{itemize}
 \end{itemize}
 \end{frame}