What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? exists z: P_4(z) -> T(z). forall z: T(z) -> U(z). forall z: R(z) <-> P_4(z).
exists z: P_4(z) -> U(z). forall z: R(z) -> P_4(z). forall z: P_4(z) -> R(z).