Translate the following inference to logic notation: There is at least one x for which if y were a sailor, then y is an astronaut. For all x, y is not a sailor. For all x, if y were an astronaut, then y is a sailor. Therefore there is at least one x for which y is not an astronaut.
exists x: P(x) -> Q(x). forall x: ~P(x). forall x: Q(x) -> P(x). Therefore exists x: ~Q(x).