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: T_2(z) -> R_3(z). forall z: R_3(z) -> T_2(z). forall z: T_2(z) -> R_3(z).
forall z: R_3(z) <-> T_2(z) can be inferred via the universal biconditional introduction rule. forall z: T_2(z) <-> R_3(z) can be inferred via the universal biconditional introduction rule. exists z: T_2(z) <-> R_3(z) can be inferred via the existential biconditional introduction rule. exists z: R_3(z) <-> T_2(z) can be inferred via the existential biconditional introduction rule.