proposition: Lemma Zgcd_coeff_b_symm : forall a b : Z, Z.abs a <> Z.abs b -> Zgcd_coeff_b a b = Zgcd_coeff_a b a.
proof: Proof. intros a b Hneq. unfold Zgcd_coeff_a, Zgcd_coeff_b in |- *. rewrite (Zgcd_duv_symm a b Hneq). auto. Qed.
imports: CoRN.model.Zmod.ZDivides Coq.Init.Wf Coq(Lia)