What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: ~U(x). forall x: U(x) -> P_2(x). exists x: P_2(x) -> U(x).
exists x: ~P_2(x). exists x: P_2(x) <-> U(x). exists x: U(x) <-> P_2(x).