proposition: Lemma mulrn_eq0 x n : (x *+ n == 0) = ((n == 0)%N || (x == 0)).
proof: Proof. by rewrite -mulr_natl mulf_eq0 pnatr_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)