A group of people sitting and standing around at night wearing costumes.
They are at a Halloween party.
A group of people wearing costumes does not mean they are at a Halloween party.
exists e2 e3 e1 e4 s1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & of(x1,x2) & for(e3,e4) & Theme(e4,x6) & Actor(e4,x3) & v_wear(e4) & n_costume(x6) & at(e3,x5) & n_night(x5) & a_around(s1) & Manner(e3,s1) & Actor(e3,x3) & v_stand(e3) & for(e1,e2) & Theme(e2,x4) & Actor(e2,x3) & v_wear(e2) & n_costume(x4) & Actor(e1,x3) & v_sit(e1) & (x2 = x3) & n_people(x2) & n_group(x1))
exists p1 x1.(n_thing(x1) & exists x2 x3.(at(x1,x2) & n_party(x2) & (x2 = x3) & ne_org_halloween(x3)))