A woman in a purple riding uniform rides a horse through a field.
A women is on a horse
For the woman to be riding a horse she needs to be on a horse.
exists e1 s1 x1 x2 x3 x4 x5.(through(e1,x5) & n_field(x5) & Theme(e1,x4) & Actor(e1,x1) & v_ride(e1) & n_horse(x4) & in(x1,x2) & n_uniform(x2) & of(x2,x3) & n_riding(x3) & a_purple(s1) & Theme(s1,x2) & n_woman(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_horse(x2)) & n_woman(x1))