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_4: W_4(z_4) or ~U(z_4). exists z_4: U(z_4).
forall z_4: U(z_4) -> W_4(z_4) can be inferred via the universal rewriting rule.