A busy crosswalk in the city.
This corner has no crosswalk.
There is either a crosswalk or no crosswalk at all.
exists s1 x1 x2.(n_city(x2) & a_topic(x1) & in(x1,x2) & n_crosswalk(x1) & a_busy(s1) & Theme(s1,x1))
exists x1.(n_corner(x1) & -exists e1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_crosswalk(x2)))