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: S_2(z) <-> P_4(z). forall z: P_4(z).
exists z: S_2(z) -> P_4(z) can be inferred via the existential biconditional elimination rule. exists z: P_4(z) -> S_2(z) can be inferred via the existential biconditional elimination rule.