What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall z: W_1(z) <-> U_1(z). forall z: ~W_1(z).
forall z: W_1(z) -> U_1(z). forall z: U_1(z) -> W_1(z). forall z: ~U_1(z).