Consider the following premises. t_3 -> t. w -> p_6. q -> t. w or q. p_6 -> t_3. Can we infer ~t from them?
 From p_6 -> t_3, t_3 -> t we can infer p_6 -> t. From w -> p_6, p_6 -> t we can infer w -> t. Finally, from w -> t, q -> t, w or q we can infer t, which contradicts ~t. Therefore, the answer is no.