316 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28

so that in the existing state of knowledge, even if the gratuitous
assumption of rapid series convergence is made, the possibility
of making a serious estimate of the constant & appears to be out
of the question.
At the same time, it should be clearly understood that these
difficulties do mot arise from the model itself but ave inherent
in the nature of things.

2.

JUSTIFICATION OF THE GENERAL MODEL WITH RESPECT TO ITS
HYPOTHESES

General Model - Hypotheses (a), (b) and (c)

The general model is based on three hypotheses:
(a) Paretian optimum and invariance of the difference
(8) - pl),
(b) unchanging production elasticities and
(c) a steady rate of growth p of primary income R, (§ 210-211
 and 230).

Hypothesis (a)

315. The assumption of a Paretian optimum can be accepted
as a first approximation, at least insofar as equivalence over
time of primary inputs and the comparison in time of their
relative productivity is concerned.
The hypothesis that the difference i(¢) - p(¢) is invariant is
an asymptotic property of capitalistic processes which can be
demonstrated on the basis of very general assumbtions (1).

(”) Arrats (1962 A) p. 702, ALLAIS (1963) $ 117 and 127 and ArrLals
1964) $ 43.

1] Allais - pag. 120