Consider the following premises. ~q_8. q_8 -> s_3. q_8 -> s_3. s_3 -> q_8. Can we infer s_3 from them? If possible, name the inference rules being used at each step.
 From s_3 -> q_8, q_8 -> s_3 we can infer s_3 <-> q_8 via biconditional introduction. From s_3 <-> q_8 we can infer s_3 -> q_8 via biconditional elimination. From s_3 -> q_8, q_8 -> s_3 we can infer s_3 <-> q_8 via biconditional introduction. Finally, from s_3 <-> q_8, ~q_8 we can infer ~s_3 via biconditional elimination, which contradicts s_3. Therefore, the answer is no.