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: S(z) and U(z). p_17 <-> r. ~r.
p_17 -> r can be inferred via the biconditional elimination rule. r -> p_17 can be inferred via the biconditional elimination rule. ~p_17 can be inferred via the biconditional elimination rule. forall z: S(z) can be inferred via the universal simplification rule. forall z: U(z) can be inferred via the universal simplification rule.