Consider the following premises. p_4 or ~q_4. p_4 -> q_4. ~q_4. Can we infer p_4 from them?
 From p_4 or ~q_4 we can infer q_4 -> p_4. From p_4 -> q_4, q_4 -> p_4 we can infer p_4 <-> q_4. Finally, from p_4 <-> q_4, ~q_4 we can infer ~p_4, which contradicts p_4. Therefore, the answer is no.