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: forall z: P_2(z) -> S(z). exists z: ~S(z). forall z: S(z) -> P_2(z). forall z: S(z) or ~P_2(z).
exists z: ~P_2(z) can be inferred via the existential modus tollens rule. forall z: P_2(z) -> S(z) can be inferred via the universal rewriting rule. forall z: P_2(z) <-> S(z) can be inferred via the universal biconditional introduction rule. forall z: S(z) <-> P_2(z) can be inferred via the universal biconditional introduction rule.