SEMAINE D'ÉTUDE SUR LE ROLE DE L’ANALYSE ECONOMETRIQUE ETC. 74

so that we have

177-8)

R_ZR, 8B _, IR, 3Y
R ER B  =R,Y

in which the ËR, &B and 8Y correspond to virtual displacements
compatible with the restraints.
Now, the conditions for Paretian optimum can be written

II7-Q)

Np _
5,

‘Rb a
YB T

where a, ©
AB... C

-, ..., 2 are the prices of the goods
2).
Carrying the values of the derivatives of R given by (117-9)
nto (117-8), we have

JR YbBB _ 5 LycY
SCSAB TN

; À

f

!) ALLAIS, Treatise on Pure Economics (1943), p. 204.

‘111 Allais - pag. 45