Consider the following premises. For all y, y will drive a car or y is an electrician. For all y, if y were an electrician, then y is a musician. For all y, if y were a musician, then y is an electrician. For all y, if y drives a car, then y is a musician. Can we infer the following from them? If we can, name the inference rule being used: There is at least one y for which y is not a musician.
 From the fact that for all y, if y were a musician, then y is an electrician, and that for all y, if y were an electrician, then y is a musician we can infer that for all y, y is a musician if and only if y is an electrician via universal biconditional introduction. From the fact that for all y, y is a musician if and only if y is an electrician we can infer that for all y, if y were an electrician, then y is a musician via universal biconditional elimination. Finally, from the fact that for all y, if y drives a car, then y is a musician, that for all y, if y were an electrician, then y is a musician, and that for all y, y will drive a car or y is an electrician we can infer that for all y, y is a musician via universal disjunction elimination, which contradicts that There is at least one y for which y is not a musician. Therefore, the answer is no.