What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? T(a_12) or ~s. forall z: T(z) -> U(z). forall z: U(z) -> T(z).
s -> T(a_12). forall z: T(z) <-> U(z). forall z: U(z) <-> T(z).