Consider the following premises. For all y_3, if y_3 were an electrician, then y_3 is a cashier. For all y_3, if y_3 were a cashier, then y_3 is writing a letter. There is at least one y_3 for which y_3 is an electrician if and only if y_3 is a cashier. For all y_3, y_3 is not a soldier. For all y_3, if y_3 writes a letter, then y_3 is a soldier. Can we infer the following from them? For all y_3, y_3 is an electrician.
 From the fact that there is at least one y_3 for which y_3 is an electrician if and only if y_3 is a cashier we can infer that there is at least one y_3 for which if y_3 were a cashier, then y_3 is an electrician. From the fact that for all y_3, if y_3 were a cashier, then y_3 is writing a letter, and that for all y_3, if y_3 writes a letter, then y_3 is a soldier we can infer that for all y_3, if y_3 were a cashier, then y_3 is a soldier. From the fact that for all y_3, if y_3 were a cashier, then y_3 is a soldier, and that for all y_3, y_3 is not a soldier we can infer that for all y_3, y_3 is not a cashier. From the fact that there is at least one y_3 for which if y_3 were a cashier, then y_3 is an electrician, and that for all y_3, if y_3 were an electrician, then y_3 is a cashier we can infer that there is at least one y_3 for which y_3 is a cashier if and only if y_3 is an electrician. Finally, from the fact that there is at least one y_3 for which y_3 is a cashier if and only if y_3 is an electrician, and that for all y_3, y_3 is not a cashier we can infer that there is at least one y_3 for which y_3 is not an electrician, which contradicts that For all y_3, y_3 is an electrician. Therefore, the answer is no.