On stage, a man in a suit plays French horn while a woman behind him plays piano.
The people are playing classical music.
Classical music isn't the only kind of music with french horns and piano.
exists e1 p1 s1 x1 x2 x3 x4.(on(e1,x4) & n_stage(x4) & exists e2 x5 x6.(Theme(e2,x6) & Actor(e2,x5) & v_play(e2) & n_piano(x6) & behind(x5,x1) & n_woman(x5)) & n_male(x1) & while(e1,p1) & Theme(e1,x3) & Actor(e1,x1) & v_play(e1) & n_horn(x3) & a_french(s1) & Theme(s1,x3) & in(x1,x2) & n_suit(x2) & n_man(x1))
exists e1 s1 x1 x2.(n_people(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_music(x2) & a_classical(s1) & Theme(s1,x2))