A young girl wearing a helmet and riding a brown horse.
A young girl is not wearing a helmet.
one girl is wearing a helmet while the other girl is not wearing a helmet
exists e2 e1 s1 s2 x1 x2 x3 x4 x5.(a_topic(x1) & Theme(e2,x5) & Actor(e2,x4) & v_ride(e2) & n_horse(x5) & a_brown(s2) & Theme(s2,x5) & (x1 = x4) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_helmet(x3) & (x1 = x2) & n_girl(x1) & a_young(s1) & Theme(s1,x1))
exists s1 x1.(-exists e1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_helmet(x2)) & n_girl(x1) & a_young(s1) & Theme(s1,x1))