本文首先探討垂直整合廠商在不同上游加成與市場規模下對提供給下游廠商之商品品質決策。透過三階段動態賽局模型，解析廠商權衡上游利潤與下游相對市佔大小之均衡決策。研究證實，最適破壞行為受上游加成與市場規模交互影響，當上游加成及市場規模足夠大時，提供給下游廠商之商品品質將提升。垂直整合廠商利潤隨著市場規模變動，呈非單調性變化，下游競爭廠商則不受市場規模影響。此外，兩廠商價格差距隨上游加成提升而單調遞減。對比無垂直整合模型顯示，獨立上游廠商恆選擇品質提升，證實垂直整合結構是形塑破壞誘因之重要關鍵。

This paper examines the quality decision of a vertically integrated firm regarding the products supplied to a downstream rival under different upstream markup rates and market sizes. Using a three-stage dynamic game model, the study characterizes the equilibrium decisions arising from the trade-off between upstream profits and downstream market share. The results show that optimal sabotage behavior is jointly determined by the upstream markup rate and market size. When both the upstream markup rate and market size are sufficiently large, the vertically integrated firm improves the quality of the products supplied to its downstream rival. The profit of the vertically integrated firm varies non-monotonically with market size, whereas the downstream competing firm’s profit is unaffected by market size. In addition, the price difference between the two firms decreases monotonically as the upstream markup rate increases. A comparison with a model without vertical integration further shows that an independent upstream firm always chooses to improve quality, confirming that vertical integration is a key determinant of sabotage incentives.

目 錄
論文審定書 i
謝辭 ii
摘要 iii
Abstract iv
目錄 v
圖次 vi
第一章 緒論 1
第一節 研究動機與目的 1
第二節 研究方法 2
第二章 文獻探討 4
第一節 垂直整合與策略性破壞行為之誘因 4
第二節 上下游利潤權衡與破壞的機會成本 4
第三節 破壞與自我破壞策略的延伸應用 5
第三章 模型設定 7
第四章 廠商的最適決策 11
第一節 競爭廠商的最適訂價 11
第二節 垂直整合廠商的最適決策 12
第三節 均衡價格、需求量與利潤 13
第四節 最適破壞程度 S_V^* 之符號判斷與比較靜態 20
第五章 模型延伸：一家上游廠商與兩家下游廠商 29
第一節 模型設定與均衡求解 29
第二節 最適策略行為與比較靜態分析 30
第三節 模型對照與架構差異分析 32
第六章 結論 33
參考文獻 35
附錄 36

圖 次
圖1 上游加成 μ 對相對產量（ Q_V^*>Q_R^*）之影響 18

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