Four musicians performing on the street.
A group of people are using musical instruments.
A musician is someone who uses musical instruments, and four people would be considered a group of people.
exists e1 x1 x2 x3.(n_street(x3) & a_topic(x1) & on(e1,x3) & Actor(e1,x2) & v_perform(e1) & (x1 = x2) & n_musician(x1) & card_eq_4(x1))
exists e1 s1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_use(e1) & n_instrument(x3) & a_musical(s1) & Theme(s1,x3) & of(x1,x2) & n_people(x2) & n_group(x1))