2,666 research outputs found
Non-Hamiltonian Actions and Lie-Algebra Cohomology of Vector Fields
Two examples of -invariant closed two-forms obtained from
forms on jet bundles, which does not admit equivariant moment maps are
presented. The corresponding cohomological obstruction is computed and shown to
coincide with a nontrivial Lie algebra cohomology class on
On rank 2 vector bundles on Fano manifolds
In this work we deal with vector bundles of rank two on a Fano manifold
with . We study the nef and pseudoeffective cones of the
corresponding projectivizations and how these cones are related to the
decomposability of the vector bundle. As consequences, we obtain the complete
list of -bundles over that have a second
-bundle structure, classify all the uniform rank two vector
bundles on this class of Fano manifolds and show the stability of
indecomposable Fano bundles (with one exception on ).Comment: Updated version with an issue correcte
Network Structure in a Link-formation Game: An Experimental Study
Network formation is frequently modeled using link-formation games and typically present a multiplicity of Nash equilibria. Cooperative refinements - such as strong or coalitional proof Nash equilibria - have been the standard tool used for equilibrium selection in these games. Non-cooperative refinements derived from the theory of global games have shown also that, for a class of payoff functions, multiplicity of equilibria disappears when the game is perturbed by introducing small amounts of incomplete information. We conducted a laboratory study evaluating the predictive power of each of these refinements in an illustrative link-formation game. Compared with cooperative game solutions, the global game approach did significantly better at predicting the strategies played by individuals in the experiment.Networks, global games, cooperative games, equilibrium selection, experimental economics
Crisis y conflictividad laboral en la producción de arándano en Entre Ríos, 2002-2009
Fil: Muñoz, Roberto. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina
Auctions with Resale Market and Asymmetric Information
In this paper we study the role of resale opportunities in secondary markets over the bidding process in first and second price auctions. This trade opportunity arises owing to the presence of two factors. On the one hand, after receiving the object, the winner obtains new information about the object’s value and on the other hand, the winner may suffer a liquidity shock that force him to sell the object regardless of his valuation. The buyer in the secondary market, however, does not know if the good is being sold because the new information reveals bad news regarding the object’s valuation, or because a liquidity shock affected the seller. Our results show that revenue equivalence still holds, and bids are usually lower than those observed in the absence of liquidity shocks.Auctions, resale market, adverse selection
The Role of Social Networks on Regulation in the Telecommunication Industry
This paper studies the welfare implications of equilibrium behavior in a market characterized by competition between two interconnected telecommunication firms, subject to constraints: the customers belong to a social network. It also shows that social networks matter because equilibrium prices and welfare critically depend on how people are socially related. Next, the model is used to study effectiveness of alternative regulatory schemes. The standard regulated environement, in which the authority defines interconnection ac cess charges as being equal to marginal costs and final prices are left to the market, is considered as a benchmark. Then, we focus on the performance of two different regulatory interventions. First, access prices are set below marginal costs to foster competition. Second, switching costs are reduced to intensify competition. The results show that the second strategy is more efective to obtain equilibrium prices closer to Ramsey's level.Access charges, social networks, random regular graphs
Nestings of rational homogeneous varieties
In this paper we study the existence of sections of universal bundles on
rational homogeneous varieties -- called nestings -- classifying them
completely in the case in which the Lie algebra of the automorphism group of
the variety is simple of classical type. In particular we show that, under this
hypothesis, nestings do not exist unless there exists a proper algebraic
subgroup of the automorphism group acting transitively on the base variety.Comment: Major revision of the exposition. To appear in Tranformation Group
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