proposition: Lemma le_is_Inf: forall N h, (forall n, h <= n -> In n N) -> N = Inf.
proof: Proof. destruct N; cbn; intros; auto. specialize (H (Z.max h0 (h + 1))). lia. Qed.
imports: Coq(ZArith Psatz Bool String List FMaps) Coq(FunctionalExtensionality) CDF(Sequences IMP)