Consider the following premises. Karen is excited and Mary is working. For all x, x will sleep if and only if x is excited. Can we infer the following from them? Karen is sleeping.
 From the fact that for all x, x will sleep if and only if x is excited we can infer that Karen is sleeping if and only if Karen is excited. From the fact that Karen is sleeping if and only if Karen is excited we can infer that if Karen were excited, then Karen is sleeping. From the fact that Karen is excited and Mary is working we can infer that Karen is excited. Finally, from the fact that if Karen were excited, then Karen is sleeping, and that Karen is excited we can infer that Karen is sleeping. Therefore, the answer is yes.