A man walking a large black horse.
A man dressed in riding gear is walking a horse
There is nothing to indicate the man is dressed in riding gear.
exists e1 s1 s2 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_walk(e1) & n_horse(x3) & a_black(s2) & Theme(s2,x3) & a_large(s1) & Theme(s1,x3) & (x1 = x2) & n_man(x1))
exists e2 e1 x1 x2 x3 x4 x5.(Theme(e2,x5) & Actor(e2,x1) & v_walk(e2) & n_horse(x5) & in(e1,x3) & n_gear(x3) & of(x3,x4) & n_riding(x4) & Theme(e1,x2) & v_dress(e1) & (x1 = x2) & n_man(x1))