proposition: Lemma CRmorph_le_inv : forall {R1 R2 : ConstructiveReals} (f : @ConstructiveRealsMorphism R1 R2) (x y : CRcarrier R1), CRmorph f x <= CRmorph f y -> x <= y.
proof: Proof. intros. intro abs. apply (CRmorph_increasing f) in abs. contradiction. Qed.
imports: QArith Qabs ConstructiveReals ConstructiveLimits ConstructiveAbs