Consider the following premises. ~w_3 or s_3. s_3 -> r_15. ~q_1. w_3 or w. w -> r_15. w_4 <-> q_1. Can we infer ~r_15 from them?
 From w_3 or w, ~w_3 or s_3 we can infer w or s_3. Finally, from w -> r_15, s_3 -> r_15, w or s_3 we can infer r_15, which contradicts ~r_15. Therefore, the answer is no.