Stable Partitions in a Model with Group-Dependent Feasible Sets.

In this paper we consider a model of group formation where group of individuals may have different feasible sets. We focus on two polar cases, increasing returns, when the set of feasible alternatives increases if a new member joins thegroup, and decreasing returns, when a new member has an opposite effect and reduces the number of alternatives available for the enlarged group. We consider two notions, stability and strong stability of group structures, that correspond to Nash and Strong Nash equilibrium of the associated non-cooperative game. We prove existence results for various classes of environments and also investigate the link between the dimensionality of the set of alternatives and the existence of stable structures.feasible sets; stable partitions; positive externality; increasing and decreasing returns

The Art of Making Everybody Happy: How to Prevent a Secession

In this paper we examine compensation schemes that prevent a threat of secession by any of a country's regions. We prove that, under quite general assumptions on the distribution of citizens' preferences, there exist transfer schemes that are secession-proof. Moreover, we show that these compensation schemes entail a degree of partial equalization among regions: the gap between advantaged regions and disadvantaged regions has to be reduced but it should never be completely eliminated. We demonstrate that in the case of a uniform distribution of the nation's citizens, the secession-proof conditions generate the 50 percent compensation rule for disadvantaged regions. Copyright 2003, International Monetary Fund

Full NLO massive gauge boson pair production at the LHC

Electroweak gauge boson pair production is a very important process at the LHC as it probes the non-abelian structure of electroweak interactions and is a background process for many searches. We present full next-to-leading order predictions for the production cross sections and distributions of on-shell massive gauge boson pair production in the Standard Model, including both QCD and electroweak corrections. The hierarchy between the ZZ, WW and WZ channels, observed in the transverse momentum distributions, will be analyzed. We will also present a comparison with experimental data for the total cross sections including a study of the theoretical uncertainties.Comment: 4 pages, 4 figures. Proceeding of the inaugural conference "Windows on the Universe" (August 11-17, Quy Nhon, Vietnam) including updated results compared to arXiv:1307.433

The stability and breakup of nations : a quantitative analysis

This paper presents a model of nations where agents vote on the optimal level of public spending. Larger nations bene t from increasing returns in the provision of public goods, but bear the costs of greater cultural heterogeneity. This tradeo induces agents' preferences over di fferent geographical con gurations, thus determining the likelihood of secessions or unions. After calibrating the model to Europe, we identify the regions prone to secession and the countries most likely to merge. As a test of the theory, we show that the model can account for the breakup of Yugoslavia and the dynamics of its disintegration. We also provide empirical support for the use of genetic distances as a proxy for cultural heterogeneity.Financial aid from the Spanish Ministry of Science (ECO2008-01300) and the Fundación BBVA 3-04X is gratefully acknowledge