Two people signing books.
People are having a book signing in a bookstore.
Just because two people signing books does not mean that they are having a book signing in a bookstore.
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_sign(e1) & n_book(x3) & (x1 = x2) & n_people(x1) & card_eq_2(x1))
exists e1 x1 x2 x3 x4.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & in(x2,x4) & n_bookstore(x4) & n_signing(x2) & of(x2,x3) & n_book(x3) & n_people(x1))