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