proposition: Lemma col_permE m n s (A : 'M_(m, n)) : col_perm s A = A *m perm_mx s^-1.
proof: Proof. by rewrite mul_row_perm mulmx1 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)