A group of people walk in the park, while some talk on phones.
A group of hipsters is in the park for a concert.
People may not necessarily be in the park for a concert.
exists e1 x1 x2 x3 x4 x5 x6.(n_park(x4) & a_topic(x1) & of(x1,x2) & while(e1,x5) & on(x5,x6) & n_phone(x6) & n_talk(x5) & in(e1,x4) & Theme(e1,x3) & v_walk(e1) & (x2 = x3) & n_people(x2) & n_group(x1))
exists p1 x1 x2 x3.(n_park(x3) & exists x4.(in(x1,x3) & for(x3,x4) & n_concert(x4)) & of(x1,x2) & n_hipster(x2) & n_group(x1))