796 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
Thus from (228-13) we have 
(233-2) 
— -ke6 
Rom = K(t)e 
with 
(233-3) 
K(t)=e(t)e"| Rell] 
where œ(f) represents the effect of technical progress and k 
and %’ are constants (1). 
It can thus be seen that at any time, the maximum value 
of Ron which can be attained will be the smaller the greater 
the value of p. 
Case of a Stationary Process 
234. The formulae corresponding to a stationary process are 
derived by putting p=o0 in the preceding relationships. As is 
to be expected, the general properties of the process given in 
$ 140 
(234-1)  9=¢, 60=0, R=R, y=v, R=R.. 
are again found. 
() Relation (211-3) and (228-4). 
11] Allais - pag. 100