Artist painting on a canvas.
A person is making a sculpture.
If one is painting one is not making a sculpture.
exists s1 x1 x2.(a_topic(x1) & on(x1,x2) & n_canvas(x2) & n_painting(x1) & a_artist(s1) & Theme(s1,x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_make(e1) & n_sculpture(x2) & n_person(x1))