853 



ill vvhicli P) is a vector depending on Ra> and /•' " in tlie following 

 way: 



(12) 





Since Jj^ is symmetrical in Aji, we get from (10): 



(1) 





and from (11] 



{II) 



^fij — F.j t — 7, (V,. r —PyT ) — 7, 6a <7 = 0. 



For Vjjf '^ — Pfif''^ we introduce the notation i'' . It is easily 

 shown that 



(13) 



t = v^/ — Pyf = —-- 



\/—R' d xf 

 From (/) follows by contracting, u=z\i: 



,iy 



(U) v; f' - P, g'^ = - i' - S, g' 



When this value is substituted into (/), we get 



(15) V ug — Pu g =: — /, ^a Ï — Aa, g b^ + 7, *« jf . 



In the supposition that also the determinant | ^''-"l does not vanish 

 this equation can be simplified by the introduction of the tensor 



(16) 



9 = . . 9 '9=19 1 



as fundamental tensor and the vector 

 (17) 



Then, because of 

 (18) 



— — t 





