Blue collar workers at a convention.
the workers are at lunch
At lunch is different than convention.
exists s1 x1 x2 x3.(a_topic(x1) & at(x1,x3) & n_convention(x3) & n_worker(x1) & of(x1,x2) & n_collar(x2) & a_blue(s1) & Theme(s1,x1))
exists p1 x1.(n_worker(x1) & exists x2.(at(x1,x2) & n_lunch(x2)))