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: W_4(z) -> P_2(z). P_2(b) <-> u_3. ~u_3. forall z: P_2(z) -> W_4(z).
P_2(b) -> u_3 can be inferred via the biconditional elimination rule. u_3 -> P_2(b) can be inferred via the biconditional elimination rule. ~P_2(b) can be inferred via the biconditional elimination rule. forall z: W_4(z) <-> P_2(z) can be inferred via the universal biconditional introduction rule. forall z: P_2(z) <-> W_4(z) can be inferred via the universal biconditional introduction rule.