A man in a cowboy outfit riding a horse and chasing a small bull.
A bull runs away as a horse chases him.
Since the man that is riding a horse and chasing a bull that is running away is likely in control of the chasing, it's unlikely that the horse chases the bull voluntarily.
exists e2 e1 s1 x1 x2 x3 x4 x5 x6 x7.(a_topic(x1) & Theme(e2,x7) & Actor(e2,x6) & v_chase(e2) & n_bull(x7) & a_small(s1) & Theme(s1,x7) & (x1 = x6) & Theme(e1,x5) & Actor(e1,x4) & v_ride(e1) & n_horse(x5) & (x1 = x4) & in(x1,x2) & n_outfit(x2) & of(x2,x3) & n_cowboy(x3) & n_man(x1))
exists e1 p1 s1 x1.(exists e2 x2.(Theme(e2,x1) & Actor(e2,x2) & v_chase(e2) & n_horse(x2)) & n_male(x1) & as(e1,p1) & a_away(s1) & Manner(e1,s1) & Actor(e1,x1) & v_run(e1) & n_bull(x1))