874 
PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
Since we have 
(336-4) Ye=0,_ for 7-9: 
4%. 
(1 
and ?- p is in general small, it follows that when an estimate 
of 7, 1s available, it is possible to derive an order of magni- 
tude of ©. 
Then if we consider all those models for which 
(336-5) 
E=1 
®, vw. 
they differ from each other by the ovder of magnitude of the 
parameter A, which is equal to unity in the exponential model. 
Since we have 
(336-6) 
0) B(o)e 77° 
?(0)- k¢(i-p) 
4 
and 
b(o)=T 
f? 
it follows that as a first approximation, ¢(0) differs relatively 
ttle from $3(0) for k=1. 
It then follows that, at least as a first approximation, A is 
greater than or smaller than unity according to whether the 
amortization is more or less vapid than that corresponding to 
" Relation (240-10) 
Relation (223-7). 
Relation (220-2) 
Allais - pag. 178