proposition: Lemma prod_sum : forall (A B : Set) (p : A * B), exists a : A, (exists b : B, p = (a, b)).
proof: Proof. intros A B p. elim p. intros y y0. split with y. split with y0. reflexivity. Qed.
imports: Bool Sumbool Arith ZArith NArith Nnat Ndec Ndigits IntMap(Allmaps) Wf_nat BDDvar_ad_nat bdd1 bdd2 bdd3 bdd4 bdd5_1 bdd5_2 bdd6 bdd7 BDDdummy_lemma_2 BDDdummy_lemma_3 BDDdummy_lemma_4 bdd8