Cournot Oligopoly and Concavo-Concave Demand

The N-firm Cournot model with general technologies is reviewed to derive generalized and unified conditions for existence of a pure strategy Nash equilibrium. Tight conditions are formulated alternatively (i) in terms of concavity of two-sided transforms of inverse demand, or (ii) as linear constraintsnon the elasticities of inverse demand and its first derivative. These conditions hold, in particular, if a firm’s marginal revenue decreases in other firms’ aggregate output, or if inverse demand is logconcave. The analysis relies on lattice-theoretic methods, engaging both cardinal and ordinal notions of supermodularity. As a byproduct, a powerful test for strict quasiconcavitynis obtained

Interdependent Preferences, Potential Games and Household Consumption

This paper presents a nonparametric model of interdependent preferences, where an individual’s consumption may be an externality on the preferences of other consumers. We assume that individual price consumption data is observed for all consumers and prove that the general model imposes few restrictions on the observed data, where the consistency requirement is Nash rationalizability. We motivate potential games as an important sub class of games where the family of concave potential games is refutable and imposes stronger restrictions on observed data. As an application of this model, we discuss inter-household consumption data. Finally, we use this framework to extend the analysis of Brown and Matzkin (1996) on refutable pure exchange economies to pure exchange economies with externalities.Potential games, Externalities, Nonparametric restrictions, Revealed Preference, Household consumption, Nash-Walras equilibrium

Cournot equilibrium uniqueness via demi-concavity

AbstractA family of oligopolies that possess a unique equilibrium was identified in the second authors doctoral dissertation. For such a family, it is therein specified a class of functions-economically related to the price function of a Cournot oligopoly – that satisfy a particular type of quasi-concavity. The first part of the present article (i) conceptualizes that type of quasi-concavity by introducing the notion of demi-concavity, (ii) considers two possible variants and (iii) provides some calculus properties. The second part, by relying on the results on demi-concavity, proves a Cournot equilibrium uniqueness theorem which is new for the journal literature and subsumes various results thereof. A third part shows an example that illustrates the novelty of the result

Necessary conditions on the existence of pure Nash equilibrium in concave games and Cournot oligopoly games

Necessary conditions for the existence of pure Nash equilibria introduced by Joó (A note on minimax theorems, Annales Univ. Sci. Budapest, 39(1996) 175-179) for concave non-cooperative games are generalized and then applied to Cournot oligopoly games. If for a specified class of games there always exists a pure Nash equilibrium, then cost functions of the firms must be convex. Analogously, if for another specified class of games there always exists a pure Nash equilibrium, then revenue functions of the firms must be concave in their respective variables

Вариационни принципи за supinf задачи с ограничения и равновесие в некооперативни игри

ИМИ-БАН, 2023 г., присъждане на образователна и научна степен "доктор" на Детелина Кирилова Камбурова. [Kamburova Detelina Kirilova; Камбурова Детелина Кирилова

The two-stage game approach to coalition formation: Where we stand and ways to go

Coalition formation is often analysed in an almost non-cooperative way, as a two-stage game that consists of a first stage comprising membership actions and a second stage with physical actions, such as the provision of a public good. We formalised this widely used approach for the case where actions are simultaneous in each stage. Herein, we give special attention to the case of a symmetric physical game. Various theoretical results, in particular, for cartel games, are provided. As they are crucial, recent results on the uniqueness of coalitional equilibria of Cournot-like physical games are reconsidered. Various concrete examples are included. Finally, we discuss research strategies to obtain results about equilibrium coalition structures with abstract physical games in terms of qualitative properties of their primitives.</p

Evolution, Bounded Rationality and Institutions

This dissertation consists of five self-contained research papers that cover theoretical work, simulation-based research, and experimental studies. My research interests are mainly focused on two interrelated areas within economics. One area is concerned with the economic consequences as well as the foundations of boundedly rational behavior. The other area is more specific and concerns the design of institutions and how they can be used to shape behavior and align incentives. The first chapter belongs to both areas, Chapters 2 and 3 cover topics from the former area, whereas the last two chapters contribute to the latter area. Chapter 1 concerns the role of trader matching with regard to the selection of market institutions by boundedly rational traders. Chapter 2 presents results on the stability of the Cournot-Nash and the Walrasian equilibrium under imitative behavior. Chapter 3 presents a model linking response times and iterative thinking and provides experimental evidence regarding the underlying processes of iterative thinking. Chapter 4 investigates the effects of a leniency mechanism on collusive bribery and tax evasion. Chapter 5 asks how the timing of punishment and the timing of the resolution of uncertainty affect deterrence of illicit behavior. In the remainder of this section I present a brief introduction for each chapter and summarize the main findings

Interdependent Preferences, Potential Games and Household Consumption

This paper presents a nonparametric model of interdependent preferences, where an individual’s consumption may be an externality on the preferences of other consumers. We assume that individual price consumption data is observed for all consumers and prove that the general model imposes few restrictions on the observed data, where the consistency requirement is Nash rationalizability. We motivate potential games as an important sub class of games where the family of concave potential games is refutable and imposes stronger restrictions on observed data. As an application of this model, we discuss inter-household consumption data. Finally, we use this framework to extend the analysis of Brown and Matzkin (1996) on refutable pure exchange economies to pure exchange economies with externalities