雙占下的製程研發——一個完整的分析架構

PROCESS R AND D IN DUOPOLY A COMPLETE ANALYTIC FRAMEWORK

本文跳脫文獻透過一階條件尋求內解的慣性，回歸以利潤極大化為基礎的反應函數，重新檢視Cournot雙占廠商在研發及生產上的決策問題，除了分析製程研發時可能存在的角解，也說明過去的相關研究就廠商研發效率進行參數範圍限制的作法，其實是沒有必要的。此外，本文發即便在兩家廠商各項參數均對稱的設定下，對稱的均衡解未必穩定。而穩定的均衡策略未必對稱在生產成本相對較高的情況下，製程研發能使市場結構由雙占轉為獨占。

We reinvestigate decisions of a Cournot duopolist on process R&D and productionby relaxing the restrictions on parameters that satisfy the second-order conditions of profitmaximization. Returning to the firms’ reaction functions derived from the profit maximization,this paper not only analyzes the case of corner solution but also suggests thatrestricting the values on parameters, as usually done in the literature, is unnecessary. Inaddition, we show that even in the symmetric firm case, the symmetric equilibrium is notnecessarily stable, whereas a stable solution is not necessarily symmetric. Moreover, givensufficiently high production cost, process R&D could turn one of the two symmetric firmsinto a monopolist in the output market.