Consider the following premises. q_16 -> u. t -> u. u -> q_16. t or ~q_7. Can we infer ~(q_7 -> q_16) from them? If possible, name the inference rules being used at each step.
 From u -> q_16, q_16 -> u we can infer u <-> q_16 via biconditional introduction. From u <-> q_16 we can infer u -> q_16 via biconditional elimination. From t or ~q_7 we can infer q_7 -> t via rewriting. From q_7 -> t, t -> u we can infer q_7 -> u via transitivity. Finally, from q_7 -> u, u -> q_16 we can infer q_7 -> q_16 via transitivity, which contradicts ~(q_7 -> q_16). Therefore, the answer is no.