What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~S(b). ~s. forall z: S(z) <-> T(z). s or u.
u. ~S(b) and ~s. ~s and ~S(b). forall z: S(z) -> T(z). forall z: T(z) -> S(z).