Nash-equilibria in a heterogeneous oligopoly with fuzzy information

We consider a model of an oligopolistic market with heterogeneous firms and products where neither the cost nor the demand functions are common knowledge. Instead, each firm only has some vague ideas about the price strategies adopted by its competitors which is modelled by a fuzzy set. In analogy to the notion of an "equilibrium of actions and beliefs" we define and characterize a generalized Nash-equilibrium and show its existence under general conditions. Furthermore, the impact of the fuzzy information on the equilibrium outcome is analyzed by means of a comparative static analysis within a particular model framework.Received: 28 May 2002, Accepted: 25 December 2002, JEL Classification: D43, D80, L13We wish to thank Bernhard F. Arnold, the editor Murat Sertel , and two anonymous referees for helpful comments. Of course, we are responsible for all remaining errors.     

Corrective Taxes under Oligopoly with Inter-Firm Externalities

Pollution externalities between polluters should be taken into account in the design of corrective taxes. When the externalities are substantial and/or the number of polluters is large, the effluent levies on these firms do not necessarily result in a deadweight loss. Consequently, the second-best tax exceeds the marginal social cost of pollution. A more general rule is that the tax rate should be greater than the marginal social cost of pollution if and only if a marginal increase in the tax rate results in opposite effects on the changes of equilibrium emission level and output.     

Endogenous Timing in a Mixed Oligopoly with Foreign Competitors: the Linear Demand Case

We introduce foreign private firms into the model of Pal (1998) and investigate the impact of the introduction of foreign private firms on the endogenous timing in a mixed oligopoly in the linear demand case. We find that the public firm chooses to be a follower of all domestic private firms and that the public firm chooses not to be a leader of all foreign private firms, which is in contrast to Matsumura (2003).     

GAME THEORETIC MODELS OF MIXED OLIGOPOLY

Abstract. In this paper we review various models that have been proposed for the study of mixed oligopoly, that is markets in which private and public firm compete on equal basis using only market instruments.     

Low information nash equilibria for oligopolistic markets

This paper deals with an infinite horizon n firm oligopoly in which firms are assumed to have incomplete information about one another's actions and profit functions. An equilibrium concept is defined that is similar to the Nash non-cooperative equilibrium, but is suitable for the information assumptions of the model. The equilibrium uses a type of bounded rationality which makes firms' computations relatively easy. This is due to an implicit assumption that computation is costly and a Bayesian approach is prohibitively costly. This low information Nash equilibrium is proved to exist, and, in addition, an adaptive expectations decision process is described which, if followed by all firms, leads to the low information Nash equilibrium.     

Exchange rates and bertrand oligopoly

The impact of exchange-rate changes on industrial prices seems ambiguous. Incomplete and even perverse pass-through has been observed: the import prices in the depreciating country decrease while those in the appreciating country increase. To explain these counterintuitive price reactions we consider a situation of international Bertrand competition: two firms, based in different countries, are selling in both countries simultaneously. The profit-maximizing duopolists set the prices for their products in each of the two markets which are segmented on the demand side. We then study the qualitative effect of an exogenous exchange-rate change on the Bertrand-Nash equilibrium. Under the strong assumption of linear demand and cost functions we have normal exchange-rate pass-through. However, allowing for more general cost structures in this simple static model enables us to show that the import prices in both countries might move in counterintuitive directions.     

N‐FIRM OLIGOPOLY WITH GENERAL ISO‐ELASTIC DEMAND

In this note oligopoly with iso‐elastic demand is analysed. Unlike previous studies we consider general iso‐elastic demand rather than the case of unit elasticity. An n‐firm Nash‐Cournot equilibrium for the case of heterogeneous constant marginal costs is derived. The main result is a closed‐form solution that shows the dependency of the equilibrium on the elasticity of demand and the share of industry costs. The result has applications to a wide range of areas in oligopoly theory by allowing comparisons across markets with different elasticities of demand.     

寡头博弈模型中的时间记忆性质与预期对模型稳定性的影响

公平竞争是市场经济的灵魂,是发挥市场力量的关键.研究寡头垄断企业的竞争行为和竞争环境对中国强化反垄断,构建更加安全公平、有效竞争的经济市场意义重大.梳理寡头垄断企业中的价格竞争和产量竞争中的模型稳定性研究情况,通过模型的边界均衡点和局部均衡点来分析模型的稳定性,对寡头博弈模型中时间的记忆性与预期对模型稳定性的影响进行分析.     

On pure-strategy Nash equilibria in price–quantity games

This paper examines the existence and characteristics of pure-strategy Nash equilibria in oligopoly models in which firms simultaneously set prices and quantities. Existence of a pure-strategy equilibrium is proved for a class of price–quantity games. If the demand function is continuous, then the equilibrium outcome is similar to that of a price-only model. With discontinuous demand and limited spillover, there are rationing equilibria in which combined production falls short of market demand. Moreover, there might again be an equilibrium reflecting the outcome of a price game. Competition in price and quantity thus yields Bertrand outcomes under a variety of market conditions.     

The welfare effect of a free trade agreement in the presence of foreign direct investment and rules of origin

This paper investigates the welfare effect of forming a free trade agreement (FTA). To receive tariff‐free treatment, firms must comply with the rules of origin (ROO). Outside firms could undertake either market‐oriented or export‐platform foreign direct investments (FDIs). ROO have the following effects: (i) An infeasible FTA may become feasible by deterring outside firms' FDIs, (ii) an FDI of a less efficient firm could replace that of an efficient firm, or (iii) FDIs made before the FTA is concluded might be eliminated. These potential effects complicate the welfare effect of the FTA and could decrease the consumer surplus.