Consider the following premises. Jennifer is excited if and only if Elisabeth is working. If Robert were a musician, then Jennifer is excited. For all y_3, y_3 will not work. Can we infer the following from them? Robert is a musician.
 From the fact that for all y_3, y_3 will not work we can infer that Elisabeth is not working. From the fact that Jennifer is excited if and only if Elisabeth is working, and that Elisabeth is not working we can infer that Jennifer is not excited. Finally, from the fact that if Robert were a musician, then Jennifer is excited, and that Jennifer is not excited we can infer that Robert is not a musician, which contradicts that Robert is a musician. Therefore, the answer is no.