A person sitting on a hill outside.
A person sits on a hill to have a picnic
A person sitting on a hill outside is not necessarily a person who sits on a hill to have a picnic.
exists e1 x1 x2 x3 x4.(a_topic(x1) & on(e1,x3) & n_outside(x3) & of(x3,x4) & n_hill(x4) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_person(x1))
exists e1 p1 x1 x2 x3.(Topic(e1,p1) & exists e2 x4.(Theme(e2,x4) & Actor(e2,x1) & v_have(e2) & n_picnic(x4)) & on(e1,x3) & n_hill(x3) & Actor(e1,x2) & v_sit(e1) & n_person(x2) & n_person(x1))