proposition: Lemma map2_mx_right_in (f : R -> R -> R) (M : 'M_(m, n)) (M' : 'M_(m, n)) : (forall i j, f (M i j) (M' i j) = M' i j) -> map2_mx f M M' = M'.
proof: Proof. by move=> fM; apply/matrixP => i j; rewrite !mxE. 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)