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PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
c) National Income 
From relation (110-1), national income is given in the 
model as 
(116-4) 
RR, 20 
dt 
and, at least in terms of a first approximation, the concepts 
which are normally used satisfv the relation 
(116-5) 
R'=R'.+ ac 
Af 
It follows immediately from (116-1), (116-3), (116-4) and 
(116-5) that, at least as a first approximation. 
(116-6) 
R=R"+ (i - po) Co 
d) Gross National Product 
Whereas the differences between C, Re and R on the one 
hand, and C’, R’c and R’ on the other, are relatively insignifi- 
cant, this is not true for the concepts of Gross National Pro- 
duct (G.N.P.) and overall amortization. 
Usual Definitions 
Under the definitions usually adopted 
(116-7) 
P—=R’ + A 
11] Allais - pag. 34