Consider the following premises. s -> q. q <-> q_16. t or ~q_16. ~t. Can we infer ~s from them? If possible, name the inference rules being used at each step.
 From t or ~q_16 we can infer q_16 -> t via rewriting. From q_16 -> t, ~t we can infer ~q_16 via modus tollens. From q <-> q_16, ~q_16 we can infer ~q via biconditional elimination. Finally, from s -> q, ~q we can infer ~s via modus tollens. Therefore, the answer is yes.