Hubert Stahn

Un modèle de concurrence monopolistique: une approche en équilibre général

This paper is devoted to the study of the existence of a general equilibrium with price making firms. I assume that each firm is able to compute an objective demand for his produced goods and uses this information in order to set prices. The definition of an objective demand is set in a context of general equilibrium and the existence of such a continuous function is proved under few assumptions. I also define a monopolistic equilibrium conditional to this objective demand and show it existence under standart assumptions.

Does Standardization Really Increase Production? Katz and Shapiro's result revisited

In market structures with network externalities, it is often asserted that there is a natural tendency toward standardization. In this paper it is argued that incompatible products may survive in static models. Like KATZ and SHAPIRO (1985), I develop a simple multi-product oligopoly in which the demand for one of these commodities increases with the number of agents consuming this good. Instead I introduce a variety of cost functions and discuss the limitations of their results of Katz and Shapiro and exhibit an example that reverses their conclusions.

Waste management and household effort: toward an enhanced ADF policy

Advanced Disposal Fees (ADF) are rather popular in waste management policies, but they cease any waste reduction effort at the household level. We propose a waved ADF policy which enhances this system by giving to the households the possibility to sign a waste reduction contract in counterpart of a lower fee. These contracts satisfy an incentive, a budget balancing and a participation constraints. For these feasible contracts, we show that this enriched ADF policy is welfare improving and always induces a waste reduction e¤ort.

Externalités de réseau, défaut de coordination et diversité des standards

Cet article est consacre au probleme de la standardisation en presence dexternalites de reseau. On y montre que lemergence de standards multiples nest pas seulement le fait dun positionnement strategique dans un contexte dynamique mais peut simplement resulter dun defaut de coordination. Lanalyse est menee au moyen dun jeu en deux etapes. Dans un premier temps, les firmes font un choix parmi deux standards puis definissent leur plan de production sachant quelles font face a une demande caracterisee par des externalites de reseau au sens de Katz et Shapiro. Dans un tel contexte, la diversite des standards subsiste a lequilibre tout en etant socialement inefficace.

Does Standardization Really Increase Production

In market structures with network externalities, it is often asserted that there is a natural tendency toward standardization. In this paper it is argued that incompatible products may survive in static models. Like Katz and Shapiro [1985], I develop a simple multi-product oligopoly in which the demand for one of these commodities increases with the number of agents consuming this good. Instead I introduce a variety of cost functions and discuss the limitations of their results of Katz and Shapiro and exhibit an example that reverses their conclusions.