Guitarist and drummer on stage at a concert.
The musicians instruct the others how to play.
The musicians are either performing at a concert or they instruct others how to play, but they cannot do both activities at the same time.
exists s1 x1 x2 x3 x4.(ne_nam_guitarist(x1) & a_topic(s1) & subset_of(x2,s1) & on(x2,x3) & at(x3,x4) & n_concert(x4) & n_stage(x3) & n_drummer(x2) & subset_of(x1,s1))
exists e1 p1 x1 x2.(-(x2 = x2) & n_person(x2) & n_musician(x1) & Theme(e1,x2) & Actor(e1,x1) & v_instruct(e1) & Topic(x2,p1) & exists e2.(Actor(e2,x2) & v_play(e2)))