A man is sitting in a chair playing guitar.
A man is playing the piano.
A man can't play guitar and piano at the same time.
exists e2 e1 x1 x2 x3.(for(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_play(e2) & n_guitar(x3) & in(e1,x2) & n_chair(x2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists e1 x1 x2.(n_piano(x2) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_man(x1))