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: ~R_2(z). forall z: R_2(z) -> U(z). exists z: U(z) -> R(z). forall z: R(z) -> R_2(z).
forall z: ~R(z) can be inferred via the universal modus tollens rule. forall z: R(z) -> U(z) can be inferred via the universal transitivity rule. exists z: U(z) -> R_2(z) can be inferred via the existential transitivity rule. exists z: R_2(z) -> R(z) can be inferred via the existential transitivity rule.