Consider the following premises. For all x_12, x_12 is a server or x_12 is not a mechanic. For all x_12, x_12 is a cashier if and only if x_12 will play squash. For all x_12, x_12 will not sleep or x_12 is a mechanic. For all x_12, x_12 will sleep or x_12 is a cashier. For all x_12, x_12 will not play squash. Can we infer the following from them? There is at least one x_12 for which x_12 is not a server.
 From the fact that for all x_12, x_12 is a server or x_12 is not a mechanic we can infer that for all x_12, if x_12 were a mechanic, then x_12 is a server. From the fact that for all x_12, x_12 will sleep or x_12 is a cashier, and that for all x_12, x_12 will not sleep or x_12 is a mechanic we can infer that for all x_12, x_12 is a cashier or x_12 is a mechanic. From the fact that for all x_12, x_12 is a cashier if and only if x_12 will play squash, and that for all x_12, x_12 will not play squash we can infer that for all x_12, x_12 is not a cashier. From the fact that for all x_12, x_12 is a cashier or x_12 is a mechanic, and that for all x_12, x_12 is not a cashier we can infer that for all x_12, x_12 is a mechanic. Finally, from the fact that for all x_12, if x_12 were a mechanic, then x_12 is a server, and that for all x_12, x_12 is a mechanic we can infer that for all x_12, x_12 is a server, which contradicts that There is at least one x_12 for which x_12 is not a server. Therefore, the answer is no.