Consider the following premises. t_2 <-> q_13. q -> t_2. q or ~t. Can we infer t -> q_13 from them?
 From t_2 <-> q_13 we can infer t_2 -> q_13. From q -> t_2, t_2 -> q_13 we can infer q -> q_13. From q or ~t we can infer t -> q. Finally, from t -> q, q -> q_13 we can infer t -> q_13. Therefore, the answer is yes.