Ulrich Schwalbe

Conventions, local interaction, and automata networks

This paper deals with the evolution of conventions in a finite population of boundedly rational players. We apply methods from the theory of automata networks to analyze the effects of different interaction structures. It is shown that the size of the reference group for each player has an important impact on the evolutionary stability of a particular convention, and that the interaction structure crucially determines the distribution of conventions in the population.

Evolution, interaction, and Nash equilibria

Abstract The paper analyzes the evolution of strategy profiles in a population of finitely many players where each player interacts only with a subset of the population. Conditions are given which guarantee that the strategy profiles converge globally resp. locally to an equilibrium state. The results, derived by using methods from the theory of iterated discrete functions, are illustrated by several examples, e.g. coordination and hawk-dove games.

The core of economies with asymmetric information

Introduction - Information in Models of General Equilibrium.- Survey of the Literature.- Exchange Economies.- Production Economies.

The core of an exchange economy with asymmetric information

This paper studies the core of an exchange economy in which agents are asymmetrically informed about states of nature. An agents information is modelled as part of his consumption set and thus as part of his consumption plans. If an agent joins a coalition, his information changes according to an exogenously given information rule, a concept introduced by B. Allen. It is shown that an exchange economy with asymmetric information generates a well defined cooperative game and that the core of this game and thus the core of the underlying economy is nonempty. In contrast to recent results, this holds independently of the given information rule.

The Role of Non-Coordinated Effects in the Assessment of Minority Shareholdings

Abstract This article focusses on the non-coordinated effects of minority shareholdings in oligopolistic markets. It is demonstrated that minority shareholdings even when they fall below the usual thresholds can lead to a significant impediment of effective competition (SIEC) on a purely non-coordinated basis. This is particularly likely in a market with differentiated products, when a firm partially acquires shareholdings in its closest competitor and when the next best alternative products are only weak substitutes.

Preisgarantien im Kraftstoffmarkt

Der vorliegende Aufsatz untersucht die Auswirkungen der von einigen Mineralolunternehmen gewahrten Preisgarantien auf die Benzinpreise. Auf Grundlagen der Daten der Markttransparenzstelle des Bundeskartellamtes wurde anhand einer Differenz-von-Differenzen Analyse untersucht, ob die insbesondere von Shell gewahrten Preisgarantien eine preiserhohende Wirkung haben. Es zeigt sich, dass in den Gebieten um die Shell-Tankstellen die Preise nach Einfuhrung der Preisgarantien signifikant angestiegen sind.

Antitrust Compliance and Abusive Behaviour

The economic literature on antitrust compliance has concentrated on cartels as the most serious competition law violation. There are, however, infringements of competition law in form of an abuse of a dominant position which have not yet been considered in detail in the economics literature on antitrust compliance. This chapter examines how a comprehensive antitrust compliance programme should deal with abusive behaviour. In a first step, such a programme should determine whether the firm under consideration holds a dominant position. This requires the definition of the relevant antitrust market and the assessment of the competitive conditions in this market. If the firm is found to be dominant, the second step of a compliance programme has to ensure that no exploitative or exclusionary practices are employed. While for exploitative abuses screens similar to those in cartel cases can be used, no simple and reliable screens for exclusionary behaviour have been devised yet. Instead, the “no economic sense” test that has been suggested as an administrable rule to identify exclusionary behaviour could be applied. Roughly speaking, this test requires that a firm is able to demonstrate that the conduct under consideration is rational for the firm absent a tendency to eliminate competition. In the digital economy particular problems arise with respect to the definition of the relevant market and the determination of dominance. This is mainly due to the two-sided nature of most platform markets. Also, new forms of abusive behaviour can emerge in the digital economy that are related to the user data a platform has collected.

Effekte verschiedener Rabattformen : Überlegungen zu einem ökonomisch fundierten Ansatz

Der vorliegende Aufsatz diskutiert die okonomischen Wirkungen von Treuerabatten im Ein-Produkt-Fall. Es zeigt sich, dass die in der letzten Zeit vorgebrachten Argumente bezuglich der ?prokompetitiven? Wirkungen solcher Rabatte mit Skepsis beurteilt werden mussen. Dies gilt insbesondere fur die unterstellten Wirkungen von Treuerabatten bei ?doppelten Gewinnaufschlagen?, bei fallenden Durchschnittskosten, bei Grosenvorteilen auf der vor- und nachgelagerten Stufe sowie im Zusammenhang mit Preisdiskriminierung und Nachfragemacht. Wir argumentieren, dass viele der behaupteten Wirkungen auch mit Rabattformen erreicht werden konnten, bei denen die Gefahr von wettbewerbsbeschrankenden Wirkungen geringer sein sollte. Unsere Skepsis beruht aber auch darauf, dass oft die Voraussetzungen fur die den Argumenten zugrunde liegenden Theorien nicht oder nicht hinreichend gegeben sind?und vor allem oft nicht hinreichend explizit gemacht werden. Allerdings mussen auch die unterstellten wettbewerbsbeschrankenden Wirkungen von Treuerabatten okonomisch besser fundiert werden. Insgesamt regt dieser Artikel die Weiterentwicklung eines an der Form des jeweiligen Rabattsystems orientierten Beurteilungsmasstabs an.

The Core of a Production Economy with Asymmetric Information

The paper analyses the core of a production economy with asymmetric information. Due to the incompleteness of information the transactions an agent can make are restricted. However, if the agent joins a coalition, his information changes according to an exogenously given information rule. The production possibilities of a coalition are described by a technology set and information that the coalition can employ in production. This information depends on the information of the coalition members and is also described by an information rule. Given that the technology sets satisfy some regularity conditions, a production economy with asymmetric information generates a well-defined cooperative game. It is shown that the core of this game and thus the core of the underlying economy is non-empty provided that the technology sets satisfy a balancedness condition. This result holds independently of the given information rules. Copyright Blackwell Publishing Ltd 2003.