Consider the following premises. t_2 -> u_3. ~p. u_3 -> t_2. p <-> t_2. Can we infer u_3 from them?
 From u_3 -> t_2, t_2 -> u_3 we can infer u_3 <-> t_2. From p <-> t_2 we can infer t_2 -> p. From t_2 -> p, ~p we can infer ~t_2. Finally, from u_3 <-> t_2, ~t_2 we can infer ~u_3, which contradicts u_3. Therefore, the answer is no.