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

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