A young lady equestrian riding a brown and white horse.
The girl is on a horse.
Young lade and girl may not mean the same thing.
exists e1 s1 s2 s3 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x4) & Actor(e1,x3) & v_ride(e1) & n_horse(x4) & a_white(s3) & Theme(s3,x4) & a_brown(s2) & Theme(s2,x4) & (x1 = x3) & n_equestrian(x1) & of(x1,x2) & n_lady(x2) & a_young(s1) & Theme(s1,x1))
exists p1 x1.(n_girl(x1) & exists x2.(on(x1,x2) & n_horse(x2)))