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