What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall z: R(z) <-> S_4(z). exists z: S_4(z) -> R(z). forall z: R(z) or ~S_4(z).
forall z: S_4(z) -> R(z). forall z: R(z) -> S_4(z). forall z: S_4(z) -> R(z).