proposition: Lemma itv_le0x i : Interval +oo -oo <= i.
proof: Proof. by case: i => [[|[]]]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(div fintype bigop order ssralg finset fingroup) mathcomp(ssrnum)