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).     

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.     

跨国公司环境责任研究——对传统观点经济学分析的修正

在寡头垄断市场条件下,只要总收入的价格弹性大于总成本的价格弹性,公司就能从承担环境责任中获利,获利的多寡取决于需求曲线的价格弹性。进一步将修正扩展到多国模型,结论显示:只要满足上述条件,跨国公司承担环境责任,以无污染的方式生产产品,全球市场价格上升,需求量下降;但总收入随价格上升而增加,利润率水平随价格上升而上升。     

WELFARE ENHANCING COORDINATION IN CONSUMER COOPERATIVES UNDER MIXED OLIGOPOLY

The recent globalization of world economies has led the retail markets of developed countries towards increasing levels of integration and strategic interdependence. A non negligible share of retail and food markets is currently served by co‐operative societies. Consistently with this trend, the consumer cooperatives have recently experienced increasing levels of integration. The main aim of this paper is to study the welfare effects of coordination among consumer cooperatives competing in quantities in a mixed oligopoly against profit‐maximizing firms. We show that, in absence of agency problems, under increasing or constant returns to scale a higher output coordination of the consumer cooperatives does not affect the total welfare as long as a nonnegative profit constraint holds in these firms. On the other hand, under decreasing returns to scale, the consumer cooperatives contribute more to social welfare when acting on behalf of all consumers. This is because, by coordinating consumers’ preferences, these firms can reduce their market output, thus helping the market to come closer to the first best. All together these results seem to provide an argument in favour of the recent process of integration involving consumer cooperatives in many developed countries.     

R&D,free entry,and social inefficiency

We employ a three-stage game model with cost-reducing research and development (R&D) that is subject to spillovers to consider the problem of excess entry under free-entry equilibrium relative to the social optimum. Firms choose to enter or exit a market in the first stage, choose R&D in the second stage and output in the final stage. Results show that there is socially inefficient or excessive entry in equilibrium. However, we uniquely demonstrate that research spillovers hold the key to whether established results regarding socially inefficient entry hold. Specifically, excessive entry occurs as long as research spillovers are relatively small, but this is not necessarily the case with large spillovers. Some policy implications are discussed.     

The effectiveness of R&D subsidies

In this paper, the effectiveness of R&D subsidies is analyzed in an oligopolistic model that we apply to the cases of international R&D competition and cooperation. We find that the existence of asymmetric information among firms on whether a rival (or partner) is being subsidized or not may play a key role in explaining whether subsidies are effective or not in increasing R&D investments. In particular, it is shown that if the existence of the subsidy is made public (e.g. because strict information release regulation about R&D subsidies is enforced) and depending on the strategic relationship between the firms’ R&D efforts, an R&D subsidy could even hurt the subsidized firm.     

Market competition, social welfare in an entry-constrained differentiated-good oligopoly

This paper studies a differentiated-good oligopoly where the socially optimal number of firms (varieties) may be smaller or greater than under the free-entry equilibrium. We show that, under certain conditions, social welfare may be higher when entry is restricted into the industry.