Consider the following premises. s_1 <-> q_9. p <-> w. ~q_9. w <-> s_1. Can we infer ~p from them? If possible, name the inference rules being used at each step.
 From s_1 <-> q_9, ~q_9 we can infer ~s_1 via biconditional elimination. From w <-> s_1, ~s_1 we can infer ~w via biconditional elimination. Finally, from p <-> w, ~w we can infer ~p via biconditional elimination. Therefore, the answer is yes.