A dog and a ball.
A canine and a toy.
A dog is a canine, a ball is a toy.
exists s1 x1 x2.(a_topic(s1) & subset_of(x2,s1) & n_ball(x2) & subset_of(x1,s1) & n_dog(x1))
exists s1 x1 x2.(a_topic(s1) & subset_of(x2,s1) & n_toy(x2) & subset_of(x1,s1) & n_canine(x1))