people riding their bikes in a race.
People are participating in a triathlon.
Just because the people are racing does not mean it is a triathlon.
exists e1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x4) & n_race(x4) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_bike(x3) & of(x3,x1) & n_thing(x1) & (x1 = x2) & n_people(x1))
exists e1 x1 x2.(in(e1,x2) & n_triathlon(x2) & Actor(e1,x1) & v_participate(e1) & n_people(x1))