Translate the following inference to logic notation: There is at least one x for which if y plays squash, then y is drinking water. For all x, if y drinks water, then y is a lawyer. For all x, if y plays squash, then y is a lawyer. For all x, if y were a lawyer, then y is playing squash. Therefore there is at least one x for which y is a lawyer if and only if y will play squash.
exists x: P(x) -> Q(x). forall x: Q(x) -> R(x). forall x: P(x) -> R(x). forall x: R(x) -> P(x). Therefore exists x: R(x) <-> P(x).