Consider the following premises. q_6 -> p_6. p_6 -> q_6. q_6 <-> w. ~p_6. Can we infer ~w from them?
 From p_6 -> q_6, q_6 -> p_6 we can infer p_6 <-> q_6. From p_6 <-> q_6, ~p_6 we can infer ~q_6. Finally, from q_6 <-> w, ~q_6 we can infer ~w. Therefore, the answer is yes.