A runner on a track.
A runner is competeing in a race.
The runner is not necessarily competing in a race.
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_track(x2) & n_runner(x1))
exists e1 x1 x2.(in(e1,x2) & n_race(x2) & Actor(e1,x1) & v_competee(e1) & n_runner(x1))