Consider the following premises. t -> r_6. r_6 <-> w_2. w_1 -> t. Can we infer w_1 -> w_2 from them?
 From w_1 -> t, t -> r_6 we can infer w_1 -> r_6. From r_6 <-> w_2 we can infer r_6 -> w_2. Finally, from w_1 -> r_6, r_6 -> w_2 we can infer w_1 -> w_2. Therefore, the answer is yes.