People sitting at tables reading or working.
A group of students performing a play.
If they are reading or working, they are not performing a play.
exists e1 x1 x2 x3 x4.(a_topic(x1) & at(e1,x3) & (n_read(x3) | n_work(x3)) & of(x3,x4) & n_table(x4) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_people(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & of(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_perform(e1) & n_play(x4) & (x2 = x3) & n_student(x2) & n_group(x1))