A woman greets a little boy.
The boy is playing with the dog.
A woman is not a boy
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_greet(e1) & n_boy(x2) & a_little(s1) & Theme(s1,x2) & n_woman(x1))
exists e1 x1 x2.(n_dog(x2) & n_boy(x1) & with(e1,x2) & Actor(e1,x1) & v_play(e1))