Consider the following premises. u_2 <-> s. p_4 <-> u_2. Can we infer ~(s -> p_4) from them?
 From u_2 <-> s we can infer s -> u_2. From p_4 <-> u_2 we can infer u_2 -> p_4. Finally, from s -> u_2, u_2 -> p_4 we can infer s -> p_4, which contradicts ~(s -> p_4). Therefore, the answer is no.