Consider the following premises. q_3 -> p_6. q_3 -> q. p_6 -> q_3. ~q. q -> q_3. Can we infer p_6 from them? If possible, name the inference rules being used at each step.
 From q_3 -> q, q -> q_3 we can infer q_3 <-> q via biconditional introduction. From p_6 -> q_3, q_3 -> p_6 we can infer p_6 <-> q_3 via biconditional introduction. From q_3 <-> q, ~q we can infer ~q_3 via biconditional elimination. Finally, from p_6 <-> q_3, ~q_3 we can infer ~p_6 via biconditional elimination, which contradicts p_6. Therefore, the answer is no.