Consider the following premises. t_4 and w. w_2 -> r. r <-> t_4. Can we infer r from them?
 From r <-> t_4 we can infer t_4 -> r. From t_4 and w we can infer t_4. From t_4 we can infer t_4 or w_2. Finally, from t_4 -> r, w_2 -> r, t_4 or w_2 we can infer r. Therefore, the answer is yes.