The captains of two football teams meet with the referee on the field before the game starts.
The two teams are rivals.
Not all football teams are rivals.
exists e1 p1 x1 x2 x3 x4 x5 x6.(n_game(x6) & n_field(x5) & n_referee(x4) & n_captain(x1) & exists e2.(Actor(e2,x6) & v_start(e2)) & before(e1,p1) & with(e1,x4) & on(x4,x5) & Actor(e1,x1) & v_meet(e1) & of(x1,x2) & n_team(x2) & of(x2,x3) & n_football(x3) & card_eq_2(x2))
exists p1 x1.(n_team(x1) & card_eq_2(x1) & exists x2.((x1 = x2) & n_rival(x2)))