Consider the following premises. w_4 -> q. ~w_4 -> u. ~q. p -> ~u. Can we infer ~p from them?
 From w_4 -> q, ~q we can infer ~w_4. From ~w_4 -> u, ~w_4 we can infer u. Finally, from p -> ~u, u we can infer ~p. Therefore, the answer is yes.