Consider the following premises. forall x_6: S(x_6). forall x_6: ~P_6(x_6). forall x_6: P_6(x_6). Can we infer forall x_6: U(x_6) from them?
 From forall x_6: P_6(x_6) we can infer forall x_6: P_6(x_6) or U(x_6). Finally, from forall x_6: P_6(x_6) or U(x_6), forall x_6: ~P_6(x_6) we can infer forall x_6: U(x_6). Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.