simplicity, we assume that the total unit-cost is independent of the strategy, i.e. ci + c2 = c. The
incumbent’s payoff is given by:
{n
ɪɪ V (χt∖ xt) — ck global
''n1 (S)
ɪɪ [v (x∕Γ>Xt) — cιqt] + C2к — nG local
t=1
where qt = max {x7fl, kt}. The potential competitor must incur a market-specific fixed cost A > 0
to enter market t. Let E be the set of all markets that player e will enter. Player e’s revenue
is υ (xf, xβ). The marginal capital cost is c > 0 and additive. The objective of player e is to
maximize its payoff given by eq. (8).
We shall call kt a market commitment, if this part of the total capacity in a multi-market firm
is assigned to market t and cannot profitably be used for production of goods sold in other local
markets. A sufficient condition for market commitments is that the marginal cost to increase local
capacity is larger than the marginal incentive to increase the output in a monopoly market at the
deterring level x. We refer to this condition as (C). More precisely,
(C C1 > .f (x,0)
Condition C simply guarantees that it is not profitable for player m to redistribute capacity to
a monopoly market, if entry occurs in other markets. If condition C is satisfied and condition D is
satisfied with equality, it is sufficient for player m to install a local capacity equal to the deterrence
level kt = X and a multi-market capacity к = nx, to deter entry.
Proposition 7 If conditions C, D and S are satisfied in the fourth version of the п-market game,
Γ∏, local capacities kt = X and global capacity k4n = nx is sufficient to deter entry.
Proof. Entry deterrence is possible in Γ∏, due to (D). Player m will choose a local strategy and
installs capacity kn = nx and kt = x for t = 1,..,n. If player e enters all markets, symmetric
incentives imply that .x"fl = x and D implies that the profit of player e is not positive. If player e
enters one market (w.l.o.g. market 1) and stays out of all other markets, the following inequality
must hold for the incumbent to deter entry
∂v ∂ ∂V ∖
(x, ■' (x)) + ci — — (X, 0) ≥ 0 (10)
xι-∣ у xt-f J
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