proposition: Lemma mul_row_perm m n p s (A : 'M_(m, n)) (B : 'M_(n, p)) : A *m row_perm s B = col_perm s^-1 A *m B.
proof: Proof. by rewrite mul_col_perm invgK. 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)