Five people are sitting inside a building.
There is nobody in the building.
You cannot have five people in a building if nobody is there.
exists e1 x1 x2.(inside(e1,x2) & n_building(x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1) & card_eq_5(x1))
exists p1 x1 x3.(n_building(x3) & -exists x2.((x1 = x2) & in(x2,x3) & n_person(x2)))