proposition: Lemma ggcd_gcd : forall a b, fst (ggcd a b) = gcd a b.
proof: Proof. unfold ggcd, gcd. intros. apply ggcdn_gcdn. Qed.
imports: BinNums Eqdep_dec EqdepFacts RelationClasses Morphisms Setoid Equalities Orders OrdersFacts GenericMinMax PeanoNat BinPosDef