#[global]
Instance CR_cv_morph
  : forall {R : ConstructiveReals} (un : nat -> CRcarrier R), CMorphisms.Proper
      (CMorphisms.respectful (CReq R) CRelationClasses.iffT) (CR_cv R un).

Lemma CR_cv_le : forall {R : ConstructiveReals} (u v : nat -> CRcarrier R) (a b : CRcarrier R), (forall n:nat, u n <= v n) -> CR_cv R u a -> CR_cv R v b -> a <= b.