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: P_3(z) or S(z). forall z: U_4(z) <-> P_3(z). exists z: ~U_4(z).
forall z: U_4(z) -> P_3(z) can be inferred via the universal biconditional elimination rule. forall z: P_3(z) -> U_4(z) can be inferred via the universal biconditional elimination rule. exists z: ~P_3(z) can be inferred via the existential biconditional elimination rule.