proposition: Lemma inj_gcd x y : 0 < x -> 0 < y -> Z.to_pos (Z.gcd x y) = Pos.gcd (Z.to_pos x) (Z.to_pos y).
proof: Proof. destruct x; easy || now destruct y. Qed.
imports: BinNums BinPos Pnat BinNat Bool Equalities GenericMinMax OrdersFacts ZAxioms ZProperties DecidableClass