Sting is singing and playing the guitar before an audience.
Mariah Carey is playing the guitar.
Sting and Mariah Carey are different artists. Playing the guitar does not have to include singing.
exists e2 e1 x1 x2 x3 x4 x5 x6.(n_guitar(x5) & n_guitar(x2) & Theme(e2,x5) & Actor(e2,x4) & v_play(e2) & before(x5,x6) & n_audience(x6) & n_sting(x4) & Theme(e1,x2) & Actor(e1,x1) & v_sing(e1) & before(x2,x3) & n_audience(x3) & n_sting(x1))
exists e1 x1 x2 x3.(n_guitar(x3) & ne_per_carey(x1) & (x1 = x2) & ne_per_mariah(x2) & Theme(e1,x3) & Actor(e1,x1) & v_play(e1))