proposition: Lemma lteif_ndivlMl C z x y : z < 0 -> x < z^-1 * y ?<= if C = (y < z * x ?<= if C).
proof: Proof. by case: C => ? /=; rewrite lter_ndivlMl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)