2 people working on the roof of a building.
2 people are on the ground.
It is impossible to be on the roof if you are on the ground.
exists e1 x1 x2 x3 x4.(n_roof(x3) & a_topic(x1) & on(e1,x3) & of(x3,x4) & n_building(x4) & Actor(e1,x2) & v_work(e1) & (x1 = x2) & n_people(x1) & n_date(x1) & a_date_day_02(x1) & a_date_day_02(x1))
exists p1 x1 x2.(n_ground(x2) & on(x1,x2) & n_people(x1) & n_date(x1) & a_date_day_02(x1) & a_date_day_02(x1))