proposition: Lemma eq_map_mx (g f : R -> S) : f =1 g -> forall (M : 'M_(m, n)), M ^ f = M ^ g.
proof: Proof. by move=> eq_fg M; apply/eq_in_map_mx. 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)