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