proposition: Lemma mulrz_eq0 x n : (x *~ n == 0) = ((n == 0) || (x == 0)).
proof: Proof. by rewrite -mulrzl mulf_eq0 intr_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)