People on the roof of a building look down on a crowded street.
People are outside.
If people are on a roof they must be outside.
exists s1 x1 x2 x3 x4 x5.(n_roof(x2) & a_topic(x1) & on(x1,x2) & of(x2,x3) & on(x3,x5) & n_street(x5) & a_crowded(s1) & Theme(s1,x5) & r_down(x3) & n_look(x3) & of(x3,x4) & n_building(x4) & n_people(x1))
exists s1 x1.(Theme(s1,x1) & a_outside(s1) & n_people(x1))