Consider the following premises. For all y_3, y_3 is not a musician. For all y_3, y_3 is a writer if and only if y_3 is happy. For all y_3, y_3 is happy if and only if y_3 is a musician. For all y_3, y_3 is a writer or y_3 is a server. Can we infer the following from them? For all y_3, y_3 is a server.
 From the fact that for all y_3, y_3 is happy if and only if y_3 is a musician, and that for all y_3, y_3 is not a musician we can infer that for all y_3, y_3 is not happy. From the fact that for all y_3, y_3 is a writer if and only if y_3 is happy we can infer that for all y_3, if y_3 were a writer, then y_3 is happy. From the fact that for all y_3, if y_3 were a writer, then y_3 is happy, and that for all y_3, y_3 is not happy we can infer that for all y_3, y_3 is not a writer. Finally, from the fact that for all y_3, y_3 is a writer or y_3 is a server, and that for all y_3, y_3 is not a writer we can infer that for all y_3, y_3 is a server. Therefore, the answer is yes.