proposition: Lemma row_mul m n p (i : 'I_m) A (B : 'M_(n, p)) : row i (A *m B) = row i A *m B.
proof: Proof. by rewrite !rowE mulmxA. 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)