本文主要目的為探討消費者所得不均度的變化對垂直產品差異化的影響。模型假設消費者所得分布為一等腰梯形分配，雙佔廠商進行一兩階段賽局，第一階段選擇產品品質，第二階段進行價格競爭。主要結果指出，所得不均度上升會使得產品品質差異化減少，其中，高品質廠商之產品品質、需求量與利潤皆會下降，低品質廠商則不一定。此外，在福利方面，所得不均度上升時，雖然消費者剩餘可能上升或下降，但因高品質廠商利潤下降幅度大，整體社會福利必會降低。

This paper aims to examine the impact of increasing income inequality on vertical production differentiation. In the model, the income distribution of consumers is an isosceles trapezoid. Two firms play a two-stage game where they choose product quality at the first stage and then compete in price at the second stage. The equilibrium results indicate that greater income inequality decreases vertical product differentiation, and lowers the product quality, demand and profit of the high-quality firm. However, it has an ambiguous effect on the low-quality firm. In addition, when income inequality increases, consumer surplus may rise or fall but social welfare must decrease.

論文審定書.....i
中文摘要.....ii
英文摘要.....iii
圖次.....v
表次.....vi
第一章：前言.....1
第二章：文獻回顧.....4
第三章：模型設定.....6
第四章：均衡分析.....9
4.1情況MM.....11
4.2情況DD.....14
4.3情況MD.....18
4.4均衡結果.....21
第五章：結論.....26
參考文獻.....28
附錄A.....30
附錄B.....31

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