A social welfare function characterizing competitive equilibria of incomplete financial markets

A classic characterization of competitive equilibria views them as feasible allocations maximizing a weighted sum of utilities. It has been applied to establish fundamental properties of the equilibrium notion, such as existence, determinacy, and computability. However, it fails for economies with missing financial markets.We give such a characterization for economies with a single commodity and missing financial markets, by an amended social welfare function. Its parameters capture both the relative importance of households welfare, through the classic welfare weights, as well as the disagreements among them as to the value of the missing markets.As a by-product, we identify the dimension of the set of interior equilibrium allocations.     

Rationale and policies for the green growth of cities and regional economies

By linking environmental quality to economic growth, green growth is emerging as a new paradigm for urban policies. The paper discusses a policy package for green growth of cities and regional economies, made of four interlocking pillars: a) greener public services and purchasing behavior, b) eco-efficiency of industrial production, c) consumer awareness and demand incentives, d) support for research and innovative applications of green technologies. Urban green growth strategies are more likely to succeed if they account for policy interventions in each of these four domains. Prioritization among the different interventions needs to be based on an accurate screening of possible complementarities among the four pillars. Within the strategy, interventions in one domain unlock positive developments in other domains. Synergies and possibilities for leverage do exist at the local level, as well as potentials for policy experimentation. More knowledge of how the local economy works and a strong capacity to pursue interdepartmental and multi-level programs are essential requisite to seize the employment and growth potentials of the low-carbon transition.     

On Non-Nash Equilibria

I consider generalisations of the Nash equilibrium concept based on the idea that in equilibrium the players' beliefs should not be contradicted, even if they could possibly be incorrect. This possibility depends on the information about opponents' behaviour available to the players in equilibrium. Therefore the players' information is crucial for this notion of equilibrium, called Conjectural Equilibrium in general and Rationalizable Conjectural Equilibrium (Rubinstein-Wolinsky 1994) when the game and the players' Bayesian rationality are common knowledge. In this paper I argue for a refinement of Rationalizable Conjectural Equilibrium showing by propositions and by examples how this equilibrium notion works and how the suitable equilibrium concept depends on the players' information.Journal of Economic LiteratureClassification Numbers: C72, D83, D82.     

Equilibrium with Default and Endogenous Collateral

We study a two‐period general equilibrium model with incomplete asset markets and default. We make collateral endogenous by allowing each seller of assets to fix the level of collateral. Sellers are required to provide collateral whose first‐period value, per unit of asset, exceeds the asset price by an arbitrarily small amount. Moreover, borrowers are also required to be fully covered by the purchase, in the first period, of state‐by‐state default insurance. These insurance contracts are offered by lenders. The insurance cost or revenue is a linear charge and plays the role of a spread penalizing borrowers who will incur in default and benefiting lenders who will suffer default. Under these assumptions, equilibrium always exists.     

L’EFFICIENCE DES COOPERATIVES DE SERVICES FINANCIERS: UNE ANALYSE DE LA CONTRIBUTION DU MILIEU*

RÉSUMÉ 1 : Le faible niveau moyen d’efficience des institutions bancaires habituellement trouvé dans les études empiriques a été qualifié de « boîte noire » par Berger et Mester (1997) . Cette étude cherche à identifier si les caractéristiques de l’environnement de même que celles qui sont propres à une coopérative d’épargne et de crédit pourraient expliquer une partie des écarts de performance apparaissant dans les scores d’efficience. Le modèle de coût que nous avons estimé est basé sur la valeur ajoutée par l’intermédiation financière. Par ailleurs, pour éviter la perte d’informations découlant de la borne à l’unité des scores d’efficience découlant du DEA, nous avons comparé les résultats d’une analyse avec le score d’efficience et de superefficience. Nos résultats montrent qu’au moins 34% des écarts de scores peuvent être expliqués par un ensemble limité de variables: taille de la coopérative, taux de capitalisation, épargne par membre, nombre de membres et type de marché.     

Decisioni di gruppo: Una rassegna dei contributi nell'ambito della teoria degli insiemi sfocati

In questo lavoro viene fornita una rassegna delle pubblicazioni più significative relative ai modelli di decisione di gruppo in ambiente sfocato (fuzzy). Particolare attenzione è stata riservata, oltre ai modelli di consenso, ai metodi per la risoluzione dei problemi di aggregazione delle preferenze individuali, per i quali si è proposta una ripartizione nelle seguenti classi: metodi euristici, metodi assiomatici e metodi di approssimazione.

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Summary The paper contains a review of contributions about the use of fuzzysets to study group decisions. The contributions about the aggregation problem are classified into heuristical methods, axiomatic methods and approximation methods.Particular attention is devoted to normal collective choice theory and consensus theory.

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Lavoro eseguito con il finanziamento C.N.R. n. 83.02619.10. I paragrafi 2.1, 2.2 e 2.3 sono dovuti a M. Fedrizzi, i paragrafi 3 e 4 a W. Ostasiewicz.