proposition: Lemma gte_dsubr y x : y \is a fin_num -> (- x + y < y) = (0 < x).
proof: Proof. by rewrite -fin_numN dual_addeE lteNl oppeK; exact: lteDr. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed