Consider the following premises. u_4 <-> u_1. q_8 -> u_4. u_1 -> q_8. Can we infer ~(u_4 -> u_1) from them?
 From u_1 -> q_8, q_8 -> u_4 we can infer u_1 -> u_4. Finally, from u_4 <-> u_1 we can infer u_4 -> u_1, which contradicts ~(u_4 -> u_1). Therefore, the answer is no.