What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: exists z: W(z) <-> S(z). forall z: W(z) or ~S(z).
forall z: S(z) -> W(z) can be inferred via the universal rewriting rule. exists z: W(z) -> S(z) can be inferred via the existential biconditional elimination rule. exists z: S(z) -> W(z) can be inferred via the existential biconditional elimination rule.