Consider the following premises. s_4 -> u. s_4 or ~q_12. q_12 or ~u. Can we infer ~(u <-> q_12) from them?
 From s_4 or ~q_12 we can infer q_12 -> s_4. From q_12 or ~u we can infer u -> q_12. From q_12 -> s_4, s_4 -> u we can infer q_12 -> u. Finally, from u -> q_12, q_12 -> u we can infer u <-> q_12, which contradicts ~(u <-> q_12). Therefore, the answer is no.