What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one y for which if y drives a car, then y is reading a book. For all y, if y reads a book, then y is driving a car. For all y, if y drives a car, then y is reading a book.
For all y, y will read a book if and only if y will drive a car. For all y, y will drive a car if and only if y will read a book. There is at least one y for which y will drive a car if and only if y will read a book. There is at least one y for which y will read a book if and only if y will drive a car.