Consider the following premises. w_2 -> t. p_13 <-> w_2. p_4 or p_13. ~t. Can we infer p_4 from them?
 From w_2 -> t, ~t we can infer ~w_2. From p_13 <-> w_2, ~w_2 we can infer ~p_13. From p_4 or p_13 we can infer ~p_13 -> p_4. Finally, from ~p_13 -> p_4, ~p_13 we can infer p_4. Therefore, the answer is yes.