Consider the following premises. For all z, if z were a musician, then z is rich. For all z, if z were a musician, then z is rich. For all z, if z were rich, then z is a musician. Can we infer the following from them? There is at least one z for which if is not true that z is rich if and only if z is a musician.
 From the fact that for all z, if z were rich, then z is a musician, and that for all z, if z were a musician, then z is rich we can infer that for all z, z is rich if and only if z is a musician. From the fact that for all z, z is rich if and only if z is a musician we can infer that for all z, if z were rich, then z is a musician. Finally, from the fact that for all z, if z were rich, then z is a musician, and that for all z, if z were a musician, then z is rich we can infer that for all z, z is rich if and only if z is a musician, which contradicts that There is at least one z for which if is not true that z is rich if and only if z is a musician. Therefore, the answer is no.