What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall z: U(z) -> P(z). forall z: R_4(z) or ~P(z). forall z: R_4(z) -> U(z).
forall z: R_4(z) -> P(z). forall z: P(z) -> R_4(z).