final products are sold to households together with those supplied by vertically integrated firms.
3 Industrial Organization
3.1 Production
At time t the instantaneous equilibrium is found by solving the model backwards from final produc-
tion to R&D given the number of blueprints invented for each organizational mode. Varieties can
be sold to final customers by two types of firms: vertically integrated firms and final assemblers. A
typical vertically integrated firm faces a demand curve derived from (4) and a marginal cost equal
to λ. It chooses its scale by maximizing its operating profit
‰ = PυУу - -X
(6)
where xυ is the amount of the intermediate input produced and yυ = xυ is the final output. Optimal
output and price are then given by:
1
a ɪɪɑ
(7)
Xυ = Уу = A ^-
and
Pυ = -∙ (8)
a
Replacing these values in (6) results in operating profit equal to
a
'' = (1 - a) a(-) 1~a , (9)
which is an increasing function of product differentiation (1 — a) and a decreasing function of the
marginal cost (λ).
Turning to the outsourcing mode, there is a one-to-one equilibrium relationship between the
number of matched assemblers, the number of matched intermediate suppliers, and the number of
outsourced varieties; they are all equal to f. The joint surplus of a matched pair of entrants is given
by the revenues from the final sales of the corresponding variety psys. This is divided according to
the bargaining weights of the two parties. Accordingly, a share (1 — ω) goes to the final assembler
10