an orchestra is playing music.
An orchestra performing
If an orchestra performs or is performing it is playing music
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_music(x2) & n_orchestra(x1))
exists e1 x1 x2.(a_topic(x1) & Actor(e1,x2) & v_perform(e1) & (x1 = x2) & n_orchestra(x1))