Four men play music on stringed instruments.
The four men are playing music together.
Just because the men are all playing instruments does not mean that they are playing together as one.
exists e1 s1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & on(x2,x3) & n_instrument(x3) & a_stringed(s1) & Theme(s1,x3) & n_music(x2) & n_man(x1) & card_eq_4(x1))
exists e1 s1 x1 x2.(n_man(x1) & card_eq_4(x1) & a_together(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_music(x2))