Consider the following premises. s_1 -> t. t_3 or ~q_10. t <-> t_3. s_1. Can we infer ~t from them?
 From t <-> t_3 we can infer t_3 -> t. From t_3 or ~q_10 we can infer q_10 -> t_3. From q_10 -> t_3, t_3 -> t we can infer q_10 -> t. From s_1 we can infer s_1 or q_10. Finally, from s_1 -> t, q_10 -> t, s_1 or q_10 we can infer t, which contradicts ~t. Therefore, the answer is no.