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: U_1(z) <-> S_3(z). forall z: T(z) -> S_3(z). forall z: U_1(z) -> S(z). forall z: U_1(z) -> T(z).
forall z: U_1(z) -> S_3(z) can be inferred via the universal transitivity rule. exists z: U_1(z) -> S_3(z) can be inferred via the existential biconditional elimination rule. exists z: S_3(z) -> U_1(z) can be inferred via the existential biconditional elimination rule.