#[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 Rcv_cauchy_mod : forall {R : ConstructiveReals}
(un : nat -> CRcarrier R) (l : CRcarrier R),
CR_cv R un l -> CR_cauchy R un.