Translate the following inference to logic notation: For all x, x_23 is rich if and only if x_23 is poor. For all x, if x_23 were a sailor, then x_23 is a poet. There is at least one x for which x_23 is poor if and only if x_23 is a taxi driver. For all x, x_23 is rich if and only if x_23 is a poet. For all x, x_23 is not a taxi driver. Therefore there is at least one x for which x_23 is not a sailor.
forall x: P(x) <-> Q(x). forall x: R(x) -> S(x). exists x: Q(x) <-> T(x). forall x: P(x) <-> S(x). forall x: ~T(x). Therefore exists x: ~R(x).