proposition: Lemma scalemxDl A x y : (x + y) *m: A = x *m: A + y *m: A.
proof: Proof. by apply/matrixP=> i j; rewrite !mxE mulrDl. 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)