proposition: Lemma Zgcd_intro_unfolded : forall a b d : Z, a <> 0%Z \/ b <> 0%Z -> (d > 0)%Z -> Zdivides d a -> Zdivides d b -> (forall q : Z, Zdivides q a /\ Zdivides q b -> Zdivides q d) -> Zgcd a b = d.
proof: Proof. intros. apply Zgcd_intro. unfold Zis_gcd in |- *. tauto. Qed.
imports: CoRN.model.Zmod.ZDivides Coq.Init.Wf Coq(Lia)