Rider riding horse as it jumps over a fence.
A horse is being ridden while jumping.
A horse is being ridden implies someone known as a rider is riding the horse.
exists p1 x1 x2 x3.(a_topic(x1) & exists e1 x4.(over(e1,x4) & n_fence(x4) & Actor(e1,x1) & v_jump(e1)) & n_thing(x1) & as(x1,p1) & n_horse(x1) & of(x1,x3) & n_riding(x3) & (x1 = x2) & ne_nam_rider(x2))
exists e1 e2 x1.(while(e1,e2) & Actor(e2,x1) & v_jump(e2) & Theme(e1,x1) & v_ride(e1) & n_horse(x1))