Machinists at work with heavy machinery.
Machinists are at a factory.
You can not infer they are at the factory.
exists s1 x1 x2 x3.(a_topic(x1) & at(x1,x2) & with(x2,x3) & n_machinery(x3) & a_heavy(s1) & Theme(s1,x3) & n_work(x2) & n_machinist(x1))
exists p1 x1.(exists x2.(at(x1,x2) & n_factory(x2)) & n_machinist(x1))