Consider the following premises. p_13 <-> q_13. q_13 and t. Can we infer p_13 from them?
 From p_13 <-> q_13 we can infer q_13 -> p_13. From q_13 and t we can infer q_13. Finally, from q_13 -> p_13, q_13 we can infer p_13. Therefore, the answer is yes.