Runners compete in a marathon.
There are people running.
Runners are people.
exists e1 x1 x2.(in(e1,x2) & n_marathon(x2) & Actor(e1,x1) & v_compete(e1) & n_runner(x1))
exists p1 x1 e1 x2 x3.((x1 = x2) & Actor(e1,x3) & v_run(e1) & (x2 = x3) & n_people(x2))