A man is singing at a concert.
The man is a popular singer
Not every man singing at a concert is a popular singer.
exists e1 x1 x2.(at(e1,x2) & n_concert(x2) & Actor(e1,x1) & v_sing(e1) & n_man(x1))
exists p1 x1.(n_man(x1) & exists s1 x2.((x1 = x2) & n_singer(x2) & a_popular(s1) & Theme(s1,x2)))