A band is performing indoors.
A band is having a school concert.
Just because the band is performing indoors does not mean it is a school concert.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_indoor(x2) & n_band(x1))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_concert(x2) & of(x2,x3) & n_school(x3) & n_band(x1))