proposition: Lemma lef_nV2 : {in neg &, {mono (@GRing.inv F) : x y /~ x <= y}}.
proof: Proof. by move=> x y hx hy /=; rewrite ler_nV2 ?inE ?unitf_lt0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)