An old man sitting on a chair selling paint.
A young man standing selling lemonade.
An old man and a young man are different people.  One is selling paint, and the other is selling lemonade
exists e1 e2 s1 x1 x2 x3 x4.(a_topic(x1) & for(e1,e2) & Theme(e2,x4) & Actor(e2,x2) & v_sell(e2) & n_paint(x4) & on(e1,x3) & n_chair(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_man(x1) & a_old(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x4) & Actor(e1,x3) & v_sell(e1) & n_lemonade(x4) & (x1 = x3) & n_standing(x1) & of(x1,x2) & n_man(x2) & a_young(s1) & Theme(s1,x1))