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PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28

These coefficients, however, cannot be taken as exogenously
given. How they are determined will be discussed in section 4.
At time zero, since the system is in equilibrium, all demand
coefficients considered together are such as to require the full
utilization both of the labour force and of the existing productive
 capacity.

B. Movements through time. — As time goes on, the following
 movements take place:

a) population increases at a steady percentage rate g,
so that

(V.I)

X,#)=X,(0) e¥ ;

b) productivity changes at a particular percentage rate of
change in each sector. It will be assumed that these rates of
change (p;) are different from one sector to another but that
they are steady through time in each sector. This means that

(V.2) a(t) =a,;(0) €

at ; (2) =a, (0) eo

1=T. 2, ... (n-1).

Most p;'s and Pr, 8 (j=1, 2, ... n- 1) are positive, but a few
of them (referring to those sectors where the exhaustion of
natural resources is particularly heavy) might be negative:

c) per-capita demand changes at a particular percentage
rate of change for each commodity. We shall denote these rates
of changes as r, ({=1, 2, ... n-1). The r;s are not constant
over time; they change as a result of a very complex process,
as has been explained in the previous chapter. The #,’s as such
are not exogenous magnitudes. in our analvsis. What has been

10] Pasinetti - pag. 72