A construction worker peering over a ledge.
Nobody is peering.
There can't be a construction worker peering if nobody is peering.
exists e1 x1 x2 x3 x4.(a_topic(x1) & over(e1,x4) & n_ledge(x4) & Actor(e1,x3) & v_peer(e1) & (x1 = x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))
-exists e1 x1.(Actor(e1,x1) & v_peer(e1) & n_person(x1))