Two surgeons performing a surgery.
The two surgeons are performing a surgery on the same person
The surgeons could be performing separate procedures, not on the same person.
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_perform(e1) & n_surgery(x3) & (x1 = x2) & n_surgeon(x1) & card_eq_2(x1))
exists e1 s1 x1 x2 x3.(n_person(x3) & a_same(s1) & Theme(s1,x3) & n_surgeon(x1) & card_eq_2(x1) & on(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_surgery(x2))