Translate the following inference to logic notation: For all x, if z reads a book, then z is a sailor. For all x, z will not read a book. There is at least one x for which z is a sailor if and only if z will read a book. Therefore there is at least one x for which z is not a sailor.
forall x: P(x) -> Q(x). forall x: ~P(x). exists x: Q(x) <-> P(x). Therefore exists x: ~Q(x).