Consider the following premises. ~q_15. t_4 or t. p -> q_15. t <-> p. Can we infer ~t_4 from them?
 From p -> q_15, ~q_15 we can infer ~p. From t <-> p, ~p we can infer ~t. From t_4 or t we can infer ~t -> t_4. Finally, from ~t -> t_4, ~t we can infer t_4, which contradicts ~t_4. Therefore, the answer is no.