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