A dog in a field.
A dog is in an airplane.
One cannot be in an airplane and in a field at the same time.
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_field(x2) & n_dog(x1))
exists p1 x1.(exists x2.(in(x1,x2) & n_airplane(x2)) & n_dog(x1))