本文探討廠商在研發與生產階段的勾結行為如何影響流程創新下的研發投入、產出、價格、廠商利潤、消費者剩餘與社會福利。模型中有兩家廠商，透過研發投入可降低單位生產成本，且研發具正向外溢效果。廠商進行兩階段賽局，第一階段為研發決策，第二階段為產量競爭。結果顯示，當產品不具替代性時，生產階段的勾結不影響均衡結果；但研發階段的勾結將提高研發投入與產量，降低價格，進而提升廠商利潤、消費者剩餘與社會福利。當產品具替代性時，生產階段勾結雖可提升研發投入與廠商利潤，但會降低消費者剩餘與社會福利；研發階段勾結的效果則取決於外溢程度，若外溢效果較高，將提升研發投入、產量與社會福利，反之若外溢效果較低，則導致研發投入與社會福利下降。此外，一旦生產階段勾結，外溢效果對市場均衡結果之反向效果的臨界值即提高，表示當生產有勾結時，需要更高的外溢，研發階段勾結才能有助研發投資增加。

This paper examines how collusion in the R&D and production stages affects R&D investment, output, prices, profits, consumer surplus, and social welfare in the context of process innovation. The model features two firms that can reduce their unit production costs through R&D investment, which also generates positive spillover effects benefiting the rival firm. Firms engage in a two-stage game: the first stage involves R&D decisions, and the second stage involves quantity competition. The results show that when products are independent and do not compete with each other, collusion in the production stage does not affect the equilibrium outcomes. In contrast, collusion in the R&D stage increases R&D investment and output, lowers prices, and improves firm profits, consumer surplus, and social welfare. When products are substitutes, collusion in the production stage raises R&D investment and firm profits but leads to a decline in consumer surplus and social welfare. The impact of R&D-stage collusion under product substitutability depends on the strength of the spillover effect. If the spillover is sufficiently strong, collusion leads to higher R&D investment, output, and social welfare; however, if the spillover is too weak, collusion reduces both R&D investment and social welfare. Additionally, once firms collude in the production stage, the spillover threshold at which the market-equilibrium effect reverses rises; put differently, when production is collusive, only a higher level of spillovers allows R&D collusion to enhance R&D investment.

論文審定書…………………………………………………………i
誌謝…………………………………………………………………ii
摘要…………………………………………………………………iii
Abstract..……………………………………………………………iv
目錄…………………………………………………………………v
圖次…………………………………………………………………vi
表次…………………………………………………………………vii
第一章 前言…………………………………………………………1
第二章 文獻回顧……………………………………………………5
第三章 模型設定……………………………………………………9
第四章 四種市場狀況下的子賽局均衡結果……………………12
4.1 市場無勾結（No Collusion, N）.....…………………………12
4.2 僅產品生產階段勾結（Production Collusion, P）………..14
4.3 僅產品研發階段勾結（R&D Collusion, R）………………..16
4.4 市場完全勾結（Full Collusion, F）…………………………19
第五章 比較分析…………………………………………………..21
5.1 產品間沒有替代性（γ = 0）…………………………………21
5.2 產品間具有替代性（γ=0.3）………………………………..27
第六章 結論………………………………………………………...41
參考文獻……………………………………………………………43

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