proposition: Lemma mulrzr x n : x * n%:~R = x *~ n.
proof: Proof. by rewrite mulrzAr mulr1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)