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Microeconomics principles and analysis phần 6

Quyết định này là công khai quan sát được. Quyết định đầu tư là rất quan trọng để phần còn lại của trò chơi. Sau đây là phổ biến kiến thức. Nếu thách thức vẫn ra ngoài, nó làm cho đặt phòng chuyên nghiệp . t mức độ và đương nhiệm làm cho độc quyền chuyên nghiệp . | 308 CHAPTER 10. STRATEGIC BEHAVIOUR amount that will cost a given amount k this decision is publicly observable. The decision on investment is crucial to the way the rest of the game works. The following is common knowledge. If the challenger stays out it makes a reservation profit level n and the incumbent makes monopoly profits nM less the cost of investment if it had been undertaken in stage 1 . If the incumbent concedes to the challenger then they share the market and each gets nj. If the investment is not undertaken then the cost of fighting is nF. If the investment is undertaken in stage 1 then it is recouped dollar for dollar should a fight occur. So if the incumbent fights it makes profits of exactly nF net of the investment cost. Now consider the equilibrium. Let us focus first on the subgame that follows on from a decision by the incumbent to invest for the case where the incumbent does not invest see Exercise 10.11 . If the challenger were to enter after this then the incumbent would find that it is more profitable to fight than concede as long as nF nJ - k. 10.25 Now consider the first stage of the game is it more profitable for the incumbent to commit the investment than just to allow the no-commitment subgame to occur Yes if the net profit to be derived from successful entry deterrence exceeds the best that the incumbent could do without committing the investment nM - k nJ. 10.26 Combining the two pieces of information in 10.25 and 10.26 we get the result that deterrence works in the sense of having a subgame-perfect equilibrium as long as k has been chosen such that Hj nF k Hm Hj. 10.27 In the light of condition 10.27 it is clear that for some values of Hf Hj and Hm it may be impossible for the incumbent to deter entry by this method of precommitting to investment. There is a natural connection with the Stackelberg duopoly model. Think of the investment as advance production costs the firm is seen to build up a war-chest in the form of an inventory .