People sitting at tables reading or working.
A bunch of people at tables in the library.
Reading or working at tables does not imply being at the library.
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 x1 x2 x3 x4.(n_library(x4) & a_topic(x1) & in(x1,x4) & at(x1,x3) & n_table(x3) & of(x1,x2) & n_people(x2) & n_bunch(x1))