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(z) or U_3(z). forall z: U_1(z) or ~R(z). exists z: U_3(z) <-> U_1(z).
forall z: R(z) -> U_1(z) can be inferred via the universal rewriting rule. exists z: U_3(z) -> U_1(z) can be inferred via the existential biconditional elimination rule. exists z: U_1(z) -> U_3(z) can be inferred via the existential biconditional elimination rule.