A group of motorcyclist are ridding through the streets.
An empty street with no motorcycles.
Group and empty are not the same.
exists e1 x1 x2 x3.(n_street(x3) & through(e1,x3) & Actor(e1,x1) & v_rid(e1) & of(x1,x2) & n_motorcyclist(x2) & n_group(x1))
exists s1 x1.(-exists x2.(a_topic(x1) & with(x1,x2) & n_motorcycle(x2)) & n_street(x1) & a_empty(s1) & Theme(s1,x1))