An equestrian rider is on a horse jumping over a plane that is on the ground.
An equestrian is riding a horse over a jump shaped like a plane at a competition.
The rider might not be at a competition; he or she could be practicing.
exists p1 s1 x1 x6.(n_ground(x6) & exists e1 p2 x2 x3 x4 x5.(on(x1,x2) & over(e1,x4) & on(x5,x6) & (x4 = x5) & n_plane(x4) & Actor(e1,x3) & v_jump(e1) & (x2 = x3) & n_horse(x2)) & n_rider(x1) & a_equestrian(s1) & Theme(s1,x1))
exists e1 e2 x1 x2 x3 x4 x5 x6.(over(e1,x3) & like(e2,x5) & at(x5,x6) & n_competition(x6) & n_plane(x5) & Theme(e2,x4) & v_shape(e2) & (x3 = x4) & n_jump(x3) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2) & n_equestrian(x1))