Consider the following premises. p -> u. q_6 -> u. ~q_6. u -> q_6. Can we infer p from them?
 From u -> q_6, q_6 -> u we can infer u <-> q_6. From u <-> q_6, ~q_6 we can infer ~u. Finally, from p -> u, ~u we can infer ~p, which contradicts p. Therefore, the answer is no.