People riding bicycles at night on a track.
People racing each other.
It cannot be inferred that the people riding bikes are racing each other.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & on(e1,x5) & n_track(x5) & at(e1,x4) & n_night(x4) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_bicycle(x3) & (x1 = x2) & n_people(x1))
exists x1 x2.(a_topic(x1) & all x3.(n_other(x3) -> exists e1.(Theme(e1,x3) & Actor(e1,x2) & v_race(e1))) & (x1 = x2) & n_people(x1))