What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_6: ~Q_6(x_6). forall x_6: U(x_6) -> Q_6(x_6). U(a_5) <-> w.
U(a_5) -> w. w -> U(a_5). forall x_6: ~U(x_6).