What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_12: P_5(x_12) -> Q_12(x_12). exists x_12: Q(x_12) -> ~U(x_12). forall x_12: P_5(x_12) or Q_4(x_12). forall x_12: Q_4(x_12) -> U(x_12). forall x_12: U(x_12) <-> Q_12(x_12).
forall x_12: U(x_12) -> Q_12(x_12). forall x_12: Q_12(x_12) -> U(x_12).