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PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28

where p is a constant that can be fixed arbitrarily in the interval

(63)

0<p<0,06 .

The basic ID-system is a highly simplified demand-supply model
 where instantaneous equilibrium is assumed,

64) demand d, = supply s,=q,

To bring out the characteristic differences as clearly as possible
the primary forms of the models have heen constructed so as
to differ only in one parameter, namely the coefficient of price p,
in the demand relation.

An ID- (or RFUE-) system. The primary form:

d,=q = -3 p +U
(6sa-b) | se t 11
SMF ÉP-st Ou With E(g lp.) =~
>

Diy

The reduced form:

(66a-b)

pe —P Paty,» E@Ip_)y=-p pi;
q:= = P_1 +97, »  E(glp_))= = Pr_1

ind

(67a-c)
Ei 0120) = E(Uy Vg000) = E(u, V2) =0;  k=1, 2, ..
The corresponding PFUE-system. The primary form:

(68a-b)

[7 —-i



4 pet vy: with E(q;lh;)= - =
Elglb,_1)= Zp

£

2] Wold - pag. 34