A surgeon and two assistants perform an operation.
A surgeon with no assistants performing an operation.
The surgeon either with two assistants or no assistants performing an operation.
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_perform(e1) & n_operation(x3) & n_assistant(x1) & card_eq_2(x1) & of(x1,x2) & n_surgeon(x2))
exists x1.(-exists e1 x2 x3 x4.(a_topic(x1) & with(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_perform(e1) & n_operation(x4) & (x2 = x3) & n_assistant(x2)) & n_surgeon(x1))