A musician playing a keyboard in a concert.
A man is performing a musical display
If a man is performing a musical display, he must be a musician. If a musician is playing a keyboard in a concert, he is performing a musical display.
exists e1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x4) & n_concert(x4) & Theme(e1,x3) & Actor(e1,x2) & v_play(e1) & n_keyboard(x3) & (x1 = x2) & n_musician(x1))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_display(x2) & a_musical(s1) & Theme(s1,x2) & n_man(x1))