proposition: Lemma itv_ge b1 b2 : ~~ (b1 < b2) -> Interval b1 b2 =i pred0.
proof: Proof. by move=> ltb12 y; apply/contraNF: ltb12; apply/lt_in_itv. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(div fintype bigop order ssralg finset fingroup) mathcomp(ssrnum)