Two greyhounds race
the two dogs are competitors in a dog race
Just because the dogs race does not mean they are competitors in a dog race.
exists x1 x2.(n_race(x1) & of(x1,x2) & n_greyhound(x2) & card_eq_2(x1) & a_topic(x1))
exists p1 x1 x2.(in(p1,x2) & n_race(x2) & of(x2,x1) & n_dog(x1) & n_dog(x1) & exists x3.((x1 = x3) & n_competitor(x3)) & card_eq_2(x1))