A crowd of people a going up and down a stairway.
there are people on the stairs
If a crowd of people are going up and down a stairway, then there are people on the stairs.
exists s1 x1 x2 x3 x4 x5 x6 x7.(a_topic(x5) & down(x5,x7) & n_stairway(x7) & of(x5,x6) & n_people(x6) & n_crowd(x5) & a_topic(x1) & n_go(x4) & rel(s1,x4) & Theme(s1,x3) & a_up(s1) & (x1 = x3) & of(x1,x2) & n_people(x2) & n_crowd(x1))
exists p1 x1 x3.(n_stair(x3) & exists x2.((x1 = x2) & on(x2,x3) & n_people(x2)))