Translate the following inference to logic notation: There is at least one x for which y_3 will not drive a car. For all x, if y_3 were a taxi driver, then y_3 is driving a car. For all x, if y_3 drives a car, then y_3 is a taxi driver. Therefore there is at least one x for which y_3 is not a taxi driver.
exists x: ~P(x). forall x: Q(x) -> P(x). forall x: P(x) -> Q(x). Therefore exists x: ~Q(x).