What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: R(x) or ~S_2(x). forall x: Q_4(x) <-> R(x). forall x: U(x) -> S_2(x). forall x: U(x) or Q_4(x).
forall x: S_2(x) -> R(x). forall x: Q_4(x) -> R(x). forall x: R(x) -> Q_4(x).