Consider the following premises. There is at least one x_8 for which if x_8 were a server, then x_8 is working. For all x_8, x_8 is not a police officer. For all x_8, x_8 is a server or x_8 will not work. For all x_8, x_8 is a police officer if and only if x_8 is a server. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_8 for which x_8 will not work.
 From the fact that for all x_8, x_8 is a server or x_8 will not work we can infer that for all x_8, if x_8 works, then x_8 is a server via universal rewriting. From the fact that for all x_8, x_8 is a police officer if and only if x_8 is a server, and that for all x_8, x_8 is not a police officer we can infer that for all x_8, x_8 is not a server via universal biconditional elimination. From the fact that there is at least one x_8 for which if x_8 were a server, then x_8 is working, and that for all x_8, if x_8 works, then x_8 is a server we can infer that there is at least one x_8 for which x_8 is a server if and only if x_8 will work via existential biconditional introduction. Finally, from the fact that there is at least one x_8 for which x_8 is a server if and only if x_8 will work, and that for all x_8, x_8 is not a server we can infer that there is at least one x_8 for which x_8 will not work via existential biconditional elimination. Therefore, the answer is yes.