proposition: Lemma nmulrz_rlt0 x n (x0 : x < 0) : x *~ n < 0 = (0 < n).
proof: Proof. by rewrite -(mulr0z x) ltr_nMz2l. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)