Three dogs walking in the grass.
The cats walk in the grass.
Dogs cannot become cats.
exists e1 x1 x2 x3.(n_grass(x3) & a_topic(x1) & in(e1,x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_dog(x1) & card_eq_3(x1))
exists e1 x1 x2.(n_grass(x2) & n_cat(x1) & in(e1,x2) & Actor(e1,x1) & v_walk(e1))