proposition: Lemma mulrnAl x y n : (x *+ n) * y = (x * y) *+ n.
proof: Proof. by elim: n => [|n IHn]; rewrite ?mul0r // !mulrS mulrDl IHn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)