Consider the following premises. There is at least one x_14 for which x_14 will play tennis. For all x_14, x_14 will sleep if and only if x_14 will play tennis. For all x_14, x_14 is a janitor. Can we infer the following from them? For all x_14, x_14 will not sleep.
 From the fact that there is at least one x_14 for which x_14 will play tennis, and that for all x_14, x_14 is a janitor we can infer that there is at least one x_14 for which x_14 will play tennis and x_14 is a janitor. From the fact that for all x_14, x_14 will sleep if and only if x_14 will play tennis we can infer that for all x_14, if x_14 plays tennis, then x_14 is sleeping. From the fact that there is at least one x_14 for which x_14 will play tennis and x_14 is a janitor we can infer that there is at least one x_14 for which x_14 will play tennis. Finally, from the fact that for all x_14, if x_14 plays tennis, then x_14 is sleeping, and that there is at least one x_14 for which x_14 will play tennis we can infer that there is at least one x_14 for which x_14 will sleep, which contradicts that For all x_14, x_14 will not sleep. Therefore, the answer is no.