Consider the following premises. p -> u_2. ~q_6. q_6 -> u_2. u_2 -> q_6. Can we infer ~p from them? If possible, name the inference rules being used at each step.
 From u_2 -> q_6, q_6 -> u_2 we can infer u_2 <-> q_6 via biconditional introduction. From u_2 <-> q_6, ~q_6 we can infer ~u_2 via biconditional elimination. Finally, from p -> u_2, ~u_2 we can infer ~p via modus tollens. Therefore, the answer is yes.