A man running on a track.
A man is running on the beach.
Track and beach are different.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_track(x3) & Actor(e1,x2) & v_run(e1) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(n_beach(x2) & on(e1,x2) & Actor(e1,x1) & v_run(e1) & n_man(x1))