A dog and two people.
there are people walking their dog
Though there are two people and a dog the people may not be walking and the dog need not be theirs so they are not walking their dog
exists s1 x1 x2.(a_topic(s1) & subset_of(x2,s1) & n_people(x2) & card_eq_2(x2) & subset_of(x1,s1) & n_dog(x1))
exists p1 x1 e1 x2 x3 x4.((x1 = x2) & Theme(e1,x4) & Actor(e1,x3) & v_walk(e1) & n_dog(x4) & of(x4,x2) & n_thing(x2) & (x2 = x3) & n_people(x2))