Four old white men are playing instruments.
Four old caucasian men are playing different instruments.
That people are playing instruments doesn't imply playing different instruments, they could all play the same instuments.
exists e1 s1 s2 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_instrument(x2) & n_man(x1) & a_white(s2) & Theme(s2,x1) & a_old(s1) & Theme(s1,x1) & card_eq_4(x1))
exists e1 s1 s2 x1 x2 x3.(n_instrument(x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & -(x2 = x3) & n_instrument(x2) & n_man(x1) & a_caucasian(s2) & Theme(s2,x1) & a_old(s1) & Theme(s1,x1) & card_eq_4(x1))