Consider the following premises. ~p_4 -> q. p <-> p_4. ~q_13. p <-> q_13. Can we infer q from them? If possible, name the inference rules being used at each step.
 From p <-> q_13, ~q_13 we can infer ~p via biconditional elimination. From p <-> p_4, ~p we can infer ~p_4 via biconditional elimination. Finally, from ~p_4 -> q, ~p_4 we can infer q via modus ponens. Therefore, the answer is yes.