( 268 ) 



t 2 a 2 d' c' /' e 2 ft 2 



c 3 a* a 2 t 2 0' ft 3 e 3 



d 3 c 3 Z> 3 a 3 /t 2 ƒ ƒ" 



e' f g> h' a 3 b* c 3 



ƒ■ e 2 /< 2 ƒ b* a 3 d' 



<7 3 /* 3 e* / 2 c 3 d* a 2 



/( 2 ƒ / 3 e 2 d 2 c 2 ft 2 



That in general A, 4= O is evident i. a. from 



The A,, gets after change of signs of some rows the form: 



