Translate the following inference to logic notation: For all x, z is an artist if and only if z is a soldier. There is at least one x for which z is a soldier or z is not an artist. Therefore there is at least one x for which z is an artist if and only if z is a soldier.
forall x: P(x) <-> Q(x). exists x: Q(x) or ~P(x). Therefore exists x: P(x) <-> Q(x).