proposition: Lemma mulrnAr x y n : x * (y *+ n) = (x * y) *+ n.
proof: Proof. by elim: n => [|n IHn]; rewrite ?mulr0 // !mulrS mulrDr IHn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)