SEMAINE D'ÉTUDE SUR LE ROLE DE L ANALYSE ECONOMETRIOUE ETC. 
126 
where Y, is gross national product, C, total consumption, and 
S, total savings. As to equilibrium relations, a typical case is 
the assumntion 
(25) 
where S, is saving and I, investment. 
Speaking generally, if the primary form of a VR- CC- or 
[D-system involves an accounting identity, an equivalent model 
can be constructed by interpreting the identity as a behavioural 
relation for one of the variables. For example, if the model 
involves the identity (24) and the two behavioural relations 
(26a-b) 
(27a-b) 
À 
IY 
> 
you 
x 
Wal 
A 
— 
05174 
“1%; 
ir 
cer Yo z,)=L, 
1» 
we obtain 
(28a-b) S,=Y, 
C,=L,(z,) - Ly(Y,, z,)+v" witn 
and under general conditions the relations (24) and (26)-i.7 
further imn!- 
(202-0 
—~ 
gis 
LAP 
PE 
+ 
EE 
3 
Liz, - 
Ly(Lylé,,, 
“5 
-t 
Turning to equilibrium relations, for example (25), the si- 
tuation is fundamentally different. The model involves one 
behavioural relation for each of the variables that are subject 
to the equilibrium assumption, and the equilibrium is regarded 
as the result of corresponding changes in an equilibrating va- 
2] Wold - pag. 15