#[global]
Instance CR_of_Q_morph_T
  : forall {R : ConstructiveReals}, CMorphisms.Proper
      (CMorphisms.respectful Qeq (CReq R)) (CR_of_Q R).

Lemma CRmult_le_compat_l : forall {R : ConstructiveReals} (r r1 r2:CRcarrier R), 0 <= r -> r1 <= r2 -> r * r1 <= r * r2.