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: ~S_3(z). forall z: S_3(z) -> P(z). forall z: P(z) -> S_3(z). forall z: P(z) -> S_3(z).
exists z: ~P(z) can be inferred via the existential modus tollens rule. exists z: ~P(z) can be inferred via the existential modus tollens rule. forall z: S_3(z) <-> P(z) can be inferred via the universal biconditional introduction rule. forall z: S_3(z) <-> P(z) can be inferred via the universal biconditional introduction rule. forall z: P(z) <-> S_3(z) can be inferred via the universal biconditional introduction rule. forall z: P(z) <-> S_3(z) can be inferred via the universal biconditional introduction rule.