Consider the following premises. forall z: U(z). forall z: P_6(z) or ~U(z). Can we infer P_6(a) from them?
 From forall z: P_6(z) or ~U(z) we can infer forall z: U(z) -> P_6(z). From forall z: U(z) -> P_6(z), forall z: U(z) we can infer forall z: P_6(z). Finally, from forall z: P_6(z) we can infer P_6(a). Therefore, the answer is yes.