Translate the following inference to logic notation: Richard is a doctor. For all x, if x_15 were a doctor, then x_15 is a carpenter. For all x, if x_15 were a carpenter, then x_15 is a doctor. Richard is not a carpenter. Therefore Elisabeth is a bartender.
P(a). forall x: P(x) -> Q(x). forall x: Q(x) -> P(x). ~Q(a). Therefore p.