傳統國貿理論認為，貿易障礙的降低會使得廠商出口成本下降，進而提高市場的競爭程度。然而，現實生活中廠商之間的聯合行為仍十分常見，因此本文分別使用啞鈴模型和產業內貿易模型探討貿易自由化與廠商勾結行為的關係。本文發現在加入不確定性的啞鈴模型下，廠商競爭的最適區位有可能為內解。在產業內貿易模型的架構下，勾結的社會福利永遠高過自給自足下的社會福利。而在兩個模型架構中，我們都得到貿易自由化會降低廠商勾結的可能性。

This paper presents two simple models to illustrate firms’ collusive conducts: the Barbell model, and the intra-industry trade model. In the first model, we take the uncertainty into account, and show that the optimal locations for firms to compete depend on the degree of risk.However, each firm locates at the opposite market if they collude. In the second model, we allow firms to produce differentiated goods.Both models find that trade liberalization tends to destabilize the collusive agreement.

論文審定書 i
摘要 ii
Abstract iii
List of Contents iv
List of Figures v
1. Introduction 1
2. Collusion in the Barbell Model 10
2.1. Collusion Agreement 15
2.2. Market Invasion and Punishment 17
2.2.1. Invasion with Location Unchanged 18
2.2.2. Invasion with Location Changed 20
3. Collusion in the Intra-industry Trade Model 24
3.1. Profit Solution 26
3.1.1. Market-sharing Agreements 27
3.1.2. Collusive Trade 28
3.2. The Impact of Trade Liberalization on the Stability of Collusion 31
3.3. Social Welfare Comparison 33
4. Concluding Remarks 36
5. References 37

Anderson, S. P., & Neven, D. J. (1991), Cournot Competition yields Spatial Agglomeration,International Economic Review, 32(4), 793-808.
Ashournia, D., Svejstrup Hansen, P., & Worm Hansen, J. (2013), Trade Liberalization and the Degree of Competition in International Duopoly,Review of International Economics,21(5), 1048-1059.
Belleflamme, P., & Bloch, F. (2004), Market Sharing Agreements and Collusive Networks,International Economic Review,45(2), 387-411.
Belleflamme, P., & Bloch, F. (2008), Sustainable Collusion on Separate Markets,Economics Letters,99(2), 384-386.
Bernheim, B. D., & Whinston, M. D. (1990), MultimarketContact and Collusive Behavior,Rand journal of economics,21(1), 1-26.
Bond, E. W., & Syropoulos, C. (2008), Trade Costs and Multimarket Collusion,The RAND Journal of Economics,39(4), 1080-1104.
Brander, J., & Krugman, P. (1983), A ‘Reciprocal Dumping’Model of International Trade,Journal of international economics,15(3), 313-321.
Clarke, R., & Collie, D. R. (2003), Product Differentiation and the Gains from Trade under Bertrand Duopoly,Canadian Journal of Economics,36(3), 658-673.
Colombo, L., & Labrecciosa, P. (2007), Sustaining Collusion under Economic Integration,Review of international economics,15(5), 905-915.
d'Aspremont, C., Gabszewicz, J. J., & Thisse, J. F. (1979), On Hotelling's" Stability in Competition"Econometrica, 47(5), 1145-1150.
d'Aspremont, C., & Motta, M. (2000), 6 Tougher price competition or lower concentration: a trade-o for anti-trust authorities?Market Structure and Competition Policy: Game-Theoretic Approaches, 125.
Friberg, R., & Ganslandt, M. (2008), Reciprocal Dumping with Product Differentiation, Review of International Economics,16(5), 942-954.
Friedman, J. W. (1971), A Non-Cooperative Equilibrium for Supergames,The Review of Economic Studies,38(1), 1-12.
Fung, K. C. (1991), Collusive Intra-Industry Trade,Canadian Journal of Economics, 24(2), 391-404.
Fung, K. C. (1992), Economic Integration as Competitive Discipline,International Economic Review, 33(4), 837-847.
Gross, J., & Holahan, W. L. (2003), Credible Collusion in Spatially Separated Markets,International Economic Review,44(1), 299-312.
Gupta, B., Pal, D., & Sarkar, J. (1997), Spatial Cournot Competition and Agglomeration in a Model of Location Choice,Regional Science and Urban Economics,27(3), 261-282.
Hamilton, J. H., Thisse, J. F., & Weskamp, A. (1989), Spatial Discrimination: Bertrand vs. Cournot in a Model of Location Choice,Regional Science and Urban Economics,19(1), 87-102.
Holahan, W. L. (1978), Cartel Problems: Comment,American Economic Review,68(5), 942-46.
Hotelling, H. (1929),Stability in Competition,Economic Journal, 39(153),41-57.
Hwang, H., & Mai, C. C. (1990), Effects of Spatial Price Discrimination on Output, Welfare, and Location,The American Economic Review, 80(3), 567-575.
Liang, W. J., Hwang, H., & Mai, C. C. (2006), Spatial Discrimination: Bertrand vs. Cournot with Asymmetric Demands,Regional Science and Urban Economics,36(6), 790-802.
Lommerud, K. E., & Sørgard, L. (2001), Trade Liberalization and Cartel Stability,Review of International Economics,9(2), 343-355.
Matsushima, N. (2001), Cournot Competition and Spatial Agglomeration Revisited,Economics Letters,73(2), 175-177.
Mayer, T. (2000), Spatial Cournot Competition and Heterogeneous Production Costs across Locations,Regional Science and Urban Economics,30(3), 325-352.
Osborne, D. K. (1976), Cartel Problems,The American Economic Review, 66(5),835-844.
Pal, D. (1998), Does Cournot Competition yield Spatial Agglomeration?Economics Letters,60(1), 49-53.
Pinto, B. (1986), Repeated Games and the ‘Reciprocal Dumping’ Model of Trade,Journal of International economics,20(3), 357-366.
Rowthorn, R. E. (1992), Intra-Industry Trade and Investment under Oligopoly: the Role of Market Size,The Economic Journal,102(411),402-414.
Schröder, P. J. (2007), Cartel Stability and Economic Integration,Review of International Economics,15(2), 313-320.