a girl wears a sign that says "free hugs".
The girl is wearing nothing.
The girl is wearing a sign and therefore wearing something.
exists e1 e2 s1 x1 x2 x3 x4.(Theme(e2,x2) & Actor(e2,x1) & v_wear(e2) & Theme(e1,x4) & Actor(e1,x3) & v_say(e1) & n_hug(x4) & a_free(s1) & Theme(s1,x4) & (x2 = x3) & n_sign(x2) & n_girl(x1))
exists x1.(n_girl(x1) & -exists e1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_thing(x2)))