#[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_open_below : forall {R : ConstructiveReals} (un : nat -> CRcarrier R) (m l : CRcarrier R), CR_cv R un l -> m < l -> { n : nat & forall i:nat, le n i -> m < un i }.