Consider the following premises. ~p_16. p_7 <-> s. ~p_7. p_16 <-> t. Can we infer s from them? If possible, name the inference rules being used at each step.
 From p_16 <-> t, ~p_16 we can infer ~t via biconditional elimination. Finally, from p_7 <-> s, ~p_7 we can infer ~s via biconditional elimination, which contradicts s. Therefore, the answer is no.