Singer performing on stage with acoustics
A person performing for a concert
Performing on stage does not always imply it is for a concert.
exists e1 x1 x2 x3.(ne_nam_singer(x1) & with(e1,x3) & n_acoustic(x3) & on(e1,x2) & n_stage(x2) & Actor(e1,x1) & v_perform(e1))
exists e1 x1 x2 x3.(a_topic(x1) & for(e1,x3) & n_concert(x3) & Actor(e1,x2) & v_perform(e1) & (x1 = x2) & n_person(x1))