proposition: Lemma ALRangeRelFind : forall R (subl subr : AssocList) k t, ALRangeRel R subl subr -> ALFind subl k = Some t -> { tr : Value & ALFind subr k = Some tr # R t tr}.
proof: Proof. induction subl as [| (kl,vl) subl Hind]; cpx; introv HAl Hf. allsimpl. destruct subr as [| (kr,vr) subr]; cpx;[]. allsimpl. repnd. subst. cases_ifd Hd; cpx. eexists; eauto. Qed.
imports: list Omega