Consider the following premises. For all y_4, y_4 will not sleep. There is at least one y_4 for which if y_4 were a soldier, then y_4 is sleeping. For all y_4, if y_4 were sad, then y_4 is a soldier. For all y_4, if y_4 sleeps, then y_4 is sad. Can we infer the following from them? There is at least one y_4 for which y_4 is not a soldier.
 From the fact that for all y_4, if y_4 sleeps, then y_4 is sad, and that for all y_4, if y_4 were sad, then y_4 is a soldier we can infer that for all y_4, if y_4 sleeps, then y_4 is a soldier. From the fact that for all y_4, if y_4 sleeps, then y_4 is a soldier, and that there is at least one y_4 for which if y_4 were a soldier, then y_4 is sleeping we can infer that there is at least one y_4 for which y_4 will sleep if and only if y_4 is a soldier. Finally, from the fact that there is at least one y_4 for which y_4 will sleep if and only if y_4 is a soldier, and that for all y_4, y_4 will not sleep we can infer that there is at least one y_4 for which y_4 is not a soldier. Therefore, the answer is yes.