Translate the following inference to logic notation: There is at least one x for which x_9 is a police officer or x_9 is not a poet. For all x, x_9 is a poet if and only if x_9 is a police officer. Therefore there is at least one x for which x_9 is a poet if and only if x_9 is a police officer.
exists x: P(x) or ~Q(x). forall x: Q(x) <-> P(x). Therefore exists x: Q(x) <-> P(x).