A red streetcar is on the street.
The car is green.
A red car is different then a green car
exists p1 s1 x1 x2.(n_street(x2) & on(x1,x2) & n_streetcar(x1) & a_red(s1) & Theme(s1,x1))
exists s1 x1.(n_car(x1) & Theme(s1,x1) & a_green(s1))