Consider the following premises. For all y, if y goes running, then y is playing squash. For all y, y will go running if and only if y will play squash. Susan is not playing squash. Can we infer the following from them? If we can, name the inference rule being used: Susan is not running.
 From the fact that for all y, y will go running if and only if y will play squash we can infer that for all y, if y plays squash, then y is running via universal biconditional elimination. From the fact that for all y, if y plays squash, then y is running, and that for all y, if y goes running, then y is playing squash we can infer that for all y, y will play squash if and only if y will go running via universal biconditional introduction. From the fact that for all y, y will play squash if and only if y will go running we can infer that Susan is playing squash if and only if Susan is running via universal instantiation. Finally, from the fact that Susan is playing squash if and only if Susan is running, and that Susan is not playing squash we can infer that Susan is not running via biconditional elimination. Therefore, the answer is yes.