192 
PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
It is now easy to determine the inverse of 9A + R’R, since 
1d 
x 
LS 
A 
+ 
yr 
AS L340 
AEE 2 
SK 
1% 
rar 
À ae 
pv 
4024 
” 
The typical (¢, #)" element is therefore 
Min (t,t) 
5 NEHV—2i — 
I 
WE] _ ptt 
) 
and so we obtain for the typical element of (gA + R’R)-—!: 
(A.9) (gA + RR) = 
rT — 
St] test 
A) ergy T= An 
771 Theil - pag. 28