proposition: Lemma subr_gt0 x y : (0 < y - x) = (x < y).
proof: Proof. by rewrite !lt_def subr_eq0 subr_ge0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)