proposition: Lemma injZ_pres_unit : fun_pres_unit _ _ injZ_fun.
proof: Proof. unfold fun_pres_unit; simpl; unfold inject_Z, Qeq. simpl; reflexivity. Qed.
imports: CPoly_Degree CoRN.model.rings.Qring Zring Qordfield CRing_Homomorphisms RingClass CRingClass Zlcm Q_can RX_deg