proposition: Lemma lboundT : lbound [set: R] = set0.
proof: Proof. rewrite predeqE => r; split => // /(_ (r - 1) Logic.I). rewrite lerBrDl addrC -lerBrDl subrr. by rewrite real_leNgt ?realE ?ler01// ?lexx// ltr01. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra) mathcomp(mathcomp_extra boolp classical_sets set_interval) Setoid