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: U(z) -> W_3(z). forall z: ~U(z). forall z: W_3(z) -> U(z). forall z: R_2(z) <-> W_3(z).
forall z: ~W_3(z) can be inferred via the universal modus tollens rule. forall z: U(z) <-> W_3(z) can be inferred via the universal biconditional introduction rule. forall z: W_3(z) <-> U(z) can be inferred via the universal biconditional introduction rule. forall z: R_2(z) -> W_3(z) can be inferred via the universal biconditional elimination rule. forall z: W_3(z) -> R_2(z) can be inferred via the universal biconditional elimination rule.