Man wearing a cowboy hat riding a horse.
a horse is walking.
riding a horse is the same as a horse who is walking with someone on it
exists e1 e2 x1 x2 x3 x4 x5 x6.(a_topic(x1) & Theme(e2,x3) & Actor(e2,x2) & v_wear(e2) & Theme(e1,x6) & Actor(e1,x5) & v_ride(e1) & n_horse(x6) & (x3 = x5) & n_hat(x3) & of(x3,x4) & n_cowboy(x4) & (x1 = x2) & n_man(x1))
exists e1 x1.(Actor(e1,x1) & v_walk(e1) & n_horse(x1))