Three people singing together.
A group singing
A group singing is rephrased as three people in these lines.
exists e1 p1 x1 x2.(a_topic(x1) & exists s1.(Theme(s1,x2) & a_together(s1)) & Topic(e1,p1) & Actor(e1,x2) & v_sing(e1) & (x1 = x2) & n_people(x1) & card_eq_3(x1))
exists e1 x1 x2.(a_topic(x1) & Actor(e1,x2) & v_sing(e1) & (x1 = x2) & n_group(x1))