The main requirements for equivalence of the core of an economy and the Walrasian equilibrium allocations are largeness and the freedom to form almost arbitrary coalitions in the Edgeworthian barter processes. We investigate whether constraints on coalition formation and coalitional barter alter...

First a non-cooperative model of network formation is investigated where link formation is one-sided and information flow is two-way. For that model, the relationship between different notions of efficient networks is studied: Pareto optimal networks on the one hand and welfare maximizing...

We present a variant of a general equilibrium model with group formation to study how changes of non-consumptive benefits from group formation impact on the well-being of group members. We identify a human relations paradox: Positive externalities increase, but none of the group members gains in...

We develop a model that combines competitive exchange of private commodities across endogenously formed groups with public good provision and global collective decisions. There is a tension between local and global collective decisions. In particular, we show that group formation and collective...

Nous analysons les phénomènes de contagion apparaissant dans des situtions d?interaction locale ou globale. Nous utilisons les réseaux de neurones pour étudier ces phénomènes. Contrairement à beaucoup de modèles, un état de système décrit la structure spatiale des choix et non pas...

We examine the validity of a macroeconomic version of the Modigliani–Miller theorem. By this, we mean that different capital structures can occur in equilibrium and that all of them are associated with the same allocation of commodities and the same welfare. We develop a general equilibrium...