A group of men are in a barber shop.
A barbershop quartet performs on stage.
Men in a barbershop are not the same as a barbershop quartet that performs on stage.
exists p1 x1 x2.(exists x3 x4.(in(x1,x3) & n_shop(x3) & of(x3,x4) & n_barber(x4)) & of(x1,x2) & n_man(x2) & n_group(x1))
exists e1 x1 x2 x3.(on(e1,x3) & n_stage(x3) & Actor(e1,x1) & v_perform(e1) & n_quartet(x1) & of(x1,x2) & n_barbershop(x2))