Consider the following premises. s <-> q_12. s_3 -> s. ~q_12. Can we infer ~s_3 from them?
 From s <-> q_12 we can infer s -> q_12. From s -> q_12, ~q_12 we can infer ~s. Finally, from s_3 -> s, ~s we can infer ~s_3. Therefore, the answer is yes.