proposition: Lemma widen_itvE x (uni : unify_itv i i) : @widen_itv x i uni = x.
proof: Proof. exact/val_inj. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool) mathcomp(ssrnat eqtype choice order ssralg ssrnum ssrint) mathcomp(interval) mathcomp(mathcomp_extra boolp) signed