The two men are riding horses to chase a white horse.
The three horses belong to the men.
Riding horses and chasing a horse does not imply they belong to the men.
exists e1 p1 x1 x2.(n_man(x1) & card_eq_2(x1) & Topic(e1,p1) & exists e2 s1 x3.(Theme(e2,x3) & Actor(e2,x1) & v_chase(e2) & n_horse(x3) & a_white(s1) & Theme(s1,x3)) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2))
exists e1 x1 x2.(n_man(x2) & n_horse(x1) & card_eq_3(x1) & to(e1,x2) & Actor(e1,x1) & v_belong(e1))