Two men are riding horses.
Two people are riding horses.
Two men implies two people, and they are riding horses.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2) & n_man(x1) & card_eq_2(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2) & n_people(x1) & card_eq_2(x1))