Consider the following premises. For all z_1, z_1 will take a plane and z_1 will play tennis. For all z_1, z_1 is a server. Can we infer the following from them? If we can, name the inference rule being used: There is at least one z_1 for which z_1 is not a server.
 From the fact that for all z_1, z_1 will take a plane and z_1 will play tennis we can infer that for all z_1, z_1 will take a plane via universal simplification. From the fact that for all z_1, z_1 is a server, and that for all z_1, z_1 will take a plane we can infer that for all z_1, z_1 is a server and z_1 will take a plane via universal conjunction. Finally, from the fact that for all z_1, z_1 is a server and z_1 will take a plane we can infer that for all z_1, z_1 is a server via universal simplification, which contradicts that There is at least one z_1 for which z_1 is not a server. Therefore, the answer is no.