A group of people are on a stage in front of an audience.
An audience is watching an empty stage.
The stage cannot be empty if there is a group of people on it.
exists p1 x1 x2 x3 x4.(in(p1,x3) & of(x3,x4) & n_audience(x4) & n_front(x3) & exists x5.(on(x1,x5) & n_stage(x5)) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_watch(e1) & n_stage(x2) & a_empty(s1) & Theme(s1,x2) & n_audience(x1))