People gathering for an event
Nobody is gathering
People gathering means that there are a group of individuals getting together does not indicate that nobody, or the absence of people, is gathering.
exists e1 x1 x2 x3.(a_topic(x1) & for(e1,x3) & n_event(x3) & Actor(e1,x2) & v_gather(e1) & (x1 = x2) & n_people(x1))
-exists e1 x1.(Actor(e1,x1) & v_gather(e1) & n_person(x1))