The horse on the left has white markings.
The horse on the right is black.
White markings does not mean that the one on the right is black.
exists e1 s1 x1 x2 x3.(n_left(x2) & n_horse(x1) & Theme(e1,x3) & Actor(e1,x1) & v_have(e1) & n_marking(x3) & a_white(s1) & Theme(s1,x3) & on(x1,x2))
exists s1 x1 x2.(n_right(x2) & n_horse(x1) & Theme(s1,x1) & a_black(s1) & on(x1,x2))