A man is sitting on the roof.
A person is outside.
YOU WOULD NEED TO BE OUTSIDE TO BE ON A ROOF.
exists e1 x1 x2.(n_roof(x2) & on(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists s1 x1.(Theme(s1,x1) & a_outside(s1) & n_person(x1))