What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y: S_2(y) -> S(y). forall y: S(y) <-> U_4(y). forall y: U_4(y) -> S_2(y).
forall y: U_4(y) -> S(y). forall y: S(y) -> U_4(y). forall y: U_4(y) -> S(y).