We study monopolistic competition under indirect additivity of preferences. This is dual to the Dixit-Stiglitz model, where direct additivity is assumed, with the CES case as the only common ground. Other examples include (perceived) demand functions that are exponential or linear. Our...

We study the organization of federations - or international unions - which decide together the provision of certain public goods. The benefit of centralization depends on the internalization of the spillovers, that of decentralization on the adaptability to local differences. We individuate as...

A marketplace such as Amazon hosts a variety of products by third party sellers and acts as a first party or private label retailer. Assuming an advantage of Amazon in logistics and of sellers in marketing, we investigate whether entry by Amazon is excessive from the point of view of consumers...

I study a model of geopolitical organization endogenizing the size of nations, of their public spending and of their degree of openness. The optimal geography may not be a stable equilibrium and the Alesina-Spolaore bias toward too many nations tends to be confirmed. However, multiple equilibria...

We study the organization of federations - or international unions - which decide together the provision of certain public goods. The benefit of centralization depends on the internalization of the spillovers, that of decentralization on the adaptability to local differences. We individuate as...

We model an international union as a group of countries deciding together the provision of certain public goods and policies because of spillovers. The countries are heterogeneous either in preferences and/or in economic fundamentals. The trade off between the benefits of coordination and the...