On stage a man with a microphone and a man with a saxophone perform.
There is a man singing while another plays a saxophone.
Just because the man has a microphone does not mean his performance includes singing.
exists e1 x1 x2 x3 x4 x5 x6.(on(e1,x6) & n_stage(x6) & Actor(e1,x1) & v_perform(e1) & with(x1,x2) & subset_of(x4,x2) & with(x4,x5) & n_saxophone(x5) & n_man(x4) & subset_of(x3,x2) & n_microphone(x3) & n_man(x1))
exists p1 x1 e1 p2 x2 x3.((x1 = x2) & exists e2 x4 x5.(Theme(e2,x5) & Actor(e2,x4) & v_play(e2) & n_saxophone(x5) & n_thing(x4)) & while(e1,p2) & Actor(e1,x3) & v_sing(e1) & (x2 = x3) & n_man(x2))