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) -> W_2(z). forall z: W(z) <-> W_2(z). forall z: W_2(z) -> W(z).
exists z: W(z) <-> W_2(z) can be inferred via the existential biconditional introduction rule. exists z: W_2(z) <-> W(z) can be inferred via the existential biconditional introduction rule. forall z: W(z) -> W_2(z) can be inferred via the universal biconditional elimination rule. forall z: W_2(z) -> W(z) can be inferred via the universal biconditional elimination rule.