proposition: Lemma close_iota : forall P Q : T -> Prop, (forall x, P x <-> Q x) -> close (iota P) (iota Q).
proof: Proof. intros P Q H. apply close_lim ; intros R HR x Hx ; apply HR, H, Hx. Qed.
imports: Coq(Reals Psatz ssreflect) Rcomplements Rbar Markov Iter Lub