What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_9: U(x_9) <-> Q_9(x_9). forall x_9: U(x_9) <-> Q_9(x_9).
forall x_9: U(x_9) -> Q_9(x_9). forall x_9: U(x_9) -> Q_9(x_9). forall x_9: Q_9(x_9) -> U(x_9). forall x_9: Q_9(x_9) -> U(x_9).