Many people are running in a race.
Some people are competing.
People running in a race are generally competing for something.
exists e1 x1 x2.(in(e1,x2) & n_race(x2) & Actor(e1,x1) & v_run(e1) & n_people(x1) & n_quantity(x1))
exists e1 x1.(Actor(e1,x1) & v_compete(e1) & n_people(x1))