(Oral Ens Mp/Mpi)

Soient {A\in\mathcal{S}_n(\mathbb{R})}, {C\in\mathcal{M}_{m,n}(\mathbb{R})} et {B\in\mathcal{S}_m(\mathbb{R})\cap\mathrm{GL}_m(\mathbb{R})}. On pose : {M=\begin{pmatrix}A&C^T\\C&B\end{pmatrix}.}