A biker jumps an obstacle.
A person is on a bicycle.
A biker is a person on the bicycle.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_jump(e1) & n_obstacle(x2) & n_biker(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_bicycle(x2)) & n_person(x1))