Consider the following premises. w_4 -> p. q -> p. p_6 -> w_4. r -> q. p_6 or r. Can we infer ~p from them?
 From p_6 -> w_4, w_4 -> p we can infer p_6 -> p. From r -> q, q -> p we can infer r -> p. Finally, from p_6 -> p, r -> p, p_6 or r we can infer p, which contradicts ~p. Therefore, the answer is no.