A crowd has gathered on a city street.
The street is deserted.
A street cannot be deserted if there is a crowd gathered on it.
exists e1 x1 x2 x3.(on(e1,x2) & n_street(x2) & of(x2,x3) & n_city(x3) & Actor(e1,x1) & v_gather(e1) & n_crowd(x1))
exists e1 x1.(n_street(x1) & Theme(e1,x1) & v_desert(e1))