proposition: Lemma mulrzA x m n : x *~ (m * n) = x *~ m *~ n.
proof: Proof. by rewrite -!scalezrE scalerA mulrC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)