Doctors and nurses performing an operation.
men and women performing an operation
Not all doctors and nurses are men and women.
exists e1 s1 x1 x2 x3 x4.(a_topic(s1) & subset_of(x2,s1) & Theme(e1,x4) & Actor(e1,x3) & v_perform(e1) & n_operation(x4) & (x2 = x3) & n_nurse(x2) & subset_of(x1,s1) & n_doctor(x1))
exists e1 s1 x1 x2 x3 x4.(a_topic(s1) & Theme(e1,x4) & Actor(e1,x3) & v_perform(e1) & n_operation(x4) & (s1 = x3) & n_woman(x2) & n_man(x1) & subset_of(x2,s1) & subset_of(x1,s1))