Two street musicians are performing, as people walk by.
There are street musicians performing their songs together.
Just because two street musicians are performing, does not necessarily mean they are performing their songs together.
exists e1 e2 s1 x1 x2 x3 x4.(as(e1,x3) & a_by(s1) & Manner(e2,s1) & Theme(e2,x4) & v_walk(e2) & (x3 = x4) & n_people(x3) & Actor(e1,x1) & v_perform(e1) & n_musician(x1) & of(x1,x2) & n_street(x2) & card_eq_2(x1))
exists p1 x1 e1 s1 x2 x3 x4 x5.((x1 = x2) & a_together(s1) & Manner(e1,s1) & Theme(e1,x5) & Actor(e1,x4) & v_perform(e1) & n_song(x5) & of(x5,x2) & n_thing(x2) & (x2 = x4) & n_musician(x2) & of(x2,x3) & n_street(x3))