臺灣博碩士論文加值系統

摘要
本文探討當產品具網路外部性且產品間可能為相容或不相容時，若外國廠商與本國廠商在本國市場進行 Cournot 競爭，本國政府的最適關稅是否仍為正。本文的結論如下。當產品相容時，網路外部性的存在有可能使 Cournot 競爭的性質成為反應曲線為正斜率的策略性互補。此時，只要邊際網路外部性夠大，則最適政策可能成為對外國廠商的進口補貼。無論最適關稅為正或負，其必然較產品不具網路外部性下的最適關稅為小。當產品不相容時，若外國廠商產品的邊際網路外部性夠大，則本國政府也應補貼外國廠商的進口。當本國廠商產品的網路外部性較外國廠商產品為大時，最適進口關稅有可能較產品無網路外部性下的最適關稅為高。

Abstract
This thesis re-investigates the optimum of import tariffs under an import duopoly Cournot game when products posses network externalities. The products of domestic and foreign firms can be either compatible or incompatible. Our key findings go as follows. When products are compatible, the characteristics of Cournot competition exhibit both the strategic substitutes and complement. Thus, as long as the marginal network externalities are large enough, the optimal import policy is to subsidize the foreign imports. The level of optimal tariffs with network externalities is higher than that of without network externalities regardless of the optimum of tariffs is positive of negative. When products are incompatible, if the marginal network externalities of the foreign firm are large enough, then the welfare-maximizing government may subsidize the foreign imports. Furthermore, when the network externalities of the domestic product are higher than those of the foreign product, the level of optimal tariffs with network externalities may be higher than that of without network externalities.

目 錄
第一章 研究動機與目的 1
第二章 文獻回顧 3
第一節 策略性貿易理論相關文獻 3
第二節 網路外部性相關文獻 5
第三章 廠商競爭 9
第一節 廠商決策 9
第二節 比較靜態分析 19
第四章 最適關稅分析 26
第一節 產品相容之最適關稅分析 26
第二節 產品不相容之最適關稅分析 29
第五章 結論 34
參考文獻 36

參考文獻
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