Translate the following inference to logic notation: For all x, y will not drink water. There is at least one x for which y will sleep if and only if y is a nurse. For all x, y will drink water or y will sleep. Therefore there is at least one x for which y is a nurse.
forall x: ~P(x). exists x: Q(x) <-> R(x). forall x: P(x) or Q(x). Therefore exists x: R(x).