190

PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28

then we have

_ ao

2
a \

0

he

de

2
-be
bh? 4 ¢2

—
"eos
ve

L_

and hence

(A5) gd + RR

b +c +29 —(bc+g) oO co]
(be+g) b'+c+29 —(be+9) …
—(be+g) b’+c+2g
\

which is an infinite band matrix in the infinite-horizon case.
The derivations will be somewhat simplified if we write (A.5)
in the following form:

(A.6)

ha 1

gA+RR
=2(bc +9)

thr

he + q)

The matrix on the right [disregarding the factor 2 (bc+ g)]
can be written as a scalar (p) times the product of two simple

71 Theil - pag. 26