Consider the following premises. q_1 -> q. u_4 <-> q. q_1 <-> u_4. Can we infer q_1 -> u_4 from them? If possible, name the inference rules being used at each step.
 From u_4 <-> q we can infer q -> u_4 via biconditional elimination. Finally, from q_1 -> q, q -> u_4 we can infer q_1 -> u_4 via transitivity. Therefore, the answer is yes.