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

Lemma CRmult_le_reg_l : forall {R : ConstructiveReals} (x y z : CRcarrier R), 0 < x -> x * y <= x * z -> y <= z.