::
`\[
\begin{array}{|c|c|c|}
\cline{2-3}
\multicolumn{1}{c|}{a_{11}} & a_{12} & a_{13}\\
\hline
a_{21} & a_{22} & a_{23}\\
\hline
a_{31} & a_{32} & a_{33}\\
\hline
a_{41} & a_{42} & a_{43}\\
\hline
\end{array}
\]
`Tuttavia non mi pare molto bella…
Ciao,
L.
