proposition: Lemma submxblock_diag (B_ : forall i, 'M[V]_(p_ i)) i : submxblock (\mxdiag_i B_ i) i i = B_ i.
proof: Proof. by rewrite mxblockK conform_mx_id eqxx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg countalg finalg zmodp)