A woman waiting by the train tracks.
Nobody is waiting
The first talks about a woman waiting, the second says nobody is waiting.
exists e1 x1 x2 x3 x4.(n_track(x3) & of(x3,x4) & n_train(x4) & a_topic(x1) & by(e1,x3) & Actor(e1,x2) & v_wait(e1) & (x1 = x2) & n_woman(x1))
-exists e1 x1.(Actor(e1,x1) & v_wait(e1) & n_person(x1))