Two people signing books.
Two people giving signatures.
Giving signatures is a rephrasing of signing books.
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.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_give(e1) & n_signature(x3) & (x1 = x2) & n_people(x1) & card_eq_2(x1))