Consider the following premises. For all y_4, y_4 is not a sailor or y_4 is excited. For all y_4, y_4 is a sailor. Can we infer the following from them? There is at least one y_4 for which neither y_4 will write a letter nor y_4 is excited.
 From the fact that for all y_4, y_4 is a sailor we can infer that for all y_4, y_4 is a sailor or y_4 will write a letter. Finally, from the fact that for all y_4, y_4 is a sailor or y_4 will write a letter, and that for all y_4, y_4 is not a sailor or y_4 is excited we can infer that for all y_4, y_4 will write a letter or y_4 is excited, which contradicts that There is at least one y_4 for which neither y_4 will write a letter nor y_4 is excited. Therefore, the answer is no.