proposition: Lemma bool_fun_neq_internal_zero : forall (cfg : BDDconfig) (node : ad), BDDconfig_OK cfg -> is_internal_node cfg node -> ~ bool_fun_eq (bool_fun_of_BDD cfg node) (bool_fun_of_BDD cfg BDDzero).
proof: Proof. intros cfg node H H0. rewrite (proj1 (bool_fun_of_BDD_semantics cfg H)). exact (proj1 (internal_node_not_constant cfg node H H0)). Qed.
imports: Bool Sumbool Arith ZArith NArith Nnat Ndec Ndigits IntMap(Allmaps) Wf_nat BDDvar_ad_nat bdd1 bdd2