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