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