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