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: Q_2(z) -> R_2(z). forall z: R_2(z) <-> P_2(z). forall z: ~P_2(z). exists z: Q_2(z) <-> S(z).
forall z: R_2(z) -> P_2(z) can be inferred via the universal biconditional elimination rule. exists z: Q_2(z) -> S(z) can be inferred via the existential biconditional elimination rule. forall z: P_2(z) -> R_2(z) can be inferred via the universal biconditional elimination rule. exists z: S(z) -> Q_2(z) can be inferred via the existential biconditional elimination rule. forall z: ~R_2(z) can be inferred via the universal biconditional elimination rule.