proposition: Lemma mulmxBr m n p (A : 'M[R]_(m, n)) (B1 B2 : 'M_(n, p)) : A *m (B1 - B2) = A *m B1 - A *m B2.
proof: Proof. by rewrite mulmxDr mulmxN. 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)