A boy in pajama pants jumps on a red couch.
There is a boy on the couch.
Boy on a couch is common in both sentences
exists e1 s1 x1 x2 x3 x4.(on(e1,x4) & n_couch(x4) & a_red(s1) & Theme(s1,x4) & Actor(e1,x1) & v_jump(e1) & in(x1,x2) & n_pants(x2) & of(x2,x3) & n_pajama(x3) & n_boy(x1))
exists p1 x1 x3.(n_couch(x3) & exists x2.((x1 = x2) & on(x2,x3) & n_boy(x2)))