A man with a ponytail plays a piano in public.
Nobody is playing piano
A man is somebody, not nobody.
exists e1 x1 x2 x3 x4.(in(e1,x4) & n_public(x4) & Theme(e1,x3) & Actor(e1,x1) & v_play(e1) & n_piano(x3) & with(x1,x2) & n_ponytail(x2) & n_man(x1))
-exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_piano(x2) & n_person(x1))