proposition: Lemma nmulrn_rle0 x n : x < 0 -> x *+ n <= 0.
proof: Proof. by move=> x_lt0; rewrite -(mulr0n x) ler_nMn2l. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)