Consider the following premises. q_6. p_6 -> q_6. q_6 -> p_6. Can we infer ~p_6 from them?
 From p_6 -> q_6, q_6 -> p_6 we can infer p_6 <-> q_6. From p_6 <-> q_6 we can infer q_6 -> p_6. Finally, from q_6 -> p_6, q_6 we can infer p_6, which contradicts ~p_6. Therefore, the answer is no.