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