Consider the following premises. For all x_13, if x_13 were rich, then x_13 is a server. For all x_13, if x_13 were rich, then x_13 is not taking a plane. There is at least one x_13 for which x_13 will take a plane. For all x_13, if x_13 were a server, then x_13 is rich. Can we infer the following from them? There is at least one x_13 for which x_13 is not a server.
 From the fact that for all x_13, if x_13 were a server, then x_13 is rich, and that for all x_13, if x_13 were rich, then x_13 is a server we can infer that for all x_13, x_13 is a server if and only if x_13 is rich. From the fact that for all x_13, if x_13 were rich, then x_13 is not taking a plane, and that there is at least one x_13 for which x_13 will take a plane we can infer that there is at least one x_13 for which x_13 is not rich. From the fact that for all x_13, x_13 is a server if and only if x_13 is rich we can infer that for all x_13, if x_13 were a server, then x_13 is rich. Finally, from the fact that for all x_13, if x_13 were a server, then x_13 is rich, and that there is at least one x_13 for which x_13 is not rich we can infer that there is at least one x_13 for which x_13 is not a server. Therefore, the answer is yes.