Consider the following premises. p_8 <-> U_3(d). u_1. forall x: ~U_3(x). Can we infer p_8 from them?
 From forall x: ~U_3(x) we can infer ~U_3(d). Finally, from p_8 <-> U_3(d), ~U_3(d) we can infer ~p_8, which contradicts p_8. Therefore, the answer is no.