Consider the following premises. For all x_11, if x_11 were a nurse, then x_11 is sleeping. For all x_11, x_11 is not rich. For all x_11, x_11 is a nurse. There is at least one x_11 for which x_11 is rich if and only if x_11 will sleep. Can we infer the following from them? There is at least one x_11 for which x_11 is a soldier.
 From the fact that for all x_11, if x_11 were a nurse, then x_11 is sleeping, and that for all x_11, x_11 is a nurse we can infer that for all x_11, x_11 will sleep. From the fact that there is at least one x_11 for which x_11 is rich if and only if x_11 will sleep, and that for all x_11, x_11 is not rich we can infer that there is at least one x_11 for which x_11 will not sleep. From the fact that for all x_11, x_11 will sleep we can infer that for all x_11, x_11 will sleep or x_11 is a soldier. Finally, from the fact that for all x_11, x_11 will sleep or x_11 is a soldier, and that there is at least one x_11 for which x_11 will not sleep we can infer that there is at least one x_11 for which x_11 is a soldier. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.