A hybrid algorithm for coalition structure generation

The current state-of-the-art algorithm for optimal coalition structure generation is IDP-IP—an algorithm that combines IDP (a dynamic programming algorithm due to Rahwan and Jennings, 2008b) with IP (a tree-search algorithm due to Rahwan et al., 2009). In this paper we analyse IDP-IP, highlight its limitations, and then develop a new approach for combining IDP with IP that overcomes these limitations

Simulation, estimation and welfare implications of monetary policies in a 3-country NOEM model

In this paper we derive a microfounded macro New Keynesian model for open economies, be them large or small. We consider habit formation in consumption, sectoral linkages, domestic and foreign governments, tradable and non-tradable final and intermediate goods and imperfect pass-through in these sectors. Sticky nominal prices and wages are modeled in a Calvo way. The model economy is composed of a continuum of infinitely-lived consumers and producers for three regions (countries). Numerical simulations and econometric estimations are presented with a focus on a small open economy member of the EMU. Welfare implications of the involved price and wage rigidities are discussedNew Keynesian open economy model, tradable and non-tradable sectors, final and intermediate goods, monetary policy rules, numerical simulations, Bayesian estimation, welfare implications

Strategic Interactions between Fiscal and Monetary Authorities in a Multi-Country New-Keynesian Model of a Monetary Union

In this paper we consider a number of key issues related to the policy coordination in a monetary union that has been recently discussed in the literature. To this end we propose a multi-country New-Keynesian model of a monetary union cast in the framework of linear quadratic differential games. Our framework can be used to simulate strategic interactions between an arbitrary number of fiscal authorities interacting in coalitions with or against the common central bank. For many parameter combinations our results confirm the findings of Beetsma et al. (2001) that for symmetric inflation and output gap shocks, fiscal coordination between all the countries is counter-productive within a monetary union. The clash between the central bank and the coalition of national governments is most intense under a symmetric inflation shocks when there is strong conflict concerning the orientation of stabilisation policies. This conflict is less pronounced under an asymmetric inflation and output gap shocks, however, still makes fiscal cooperation unattractive. We extend the existing New-Keynesian literature on policy coordination by considering not only cases of non-coordination, fiscal cooperation and the grand coalition, but also the partial cooperation arrangements between fiscal players. We show that, in many cases, partial fiscal coordination of a subgroup of fiscal players is more efficient, from the social point of view, than non-coordination. However, this regime still delivers poor results from the perspective of individual players. This occurs especially in the case of asymmetric shocks, as the countries directly affected by the shocks tend to "export" losses to the countries with whom they form a coalition. Furthermore, we show that the common objective of the grand coalition is of the upmost importance for the outcome of the stabilisation process.macroeconomic stabilisation, EMU, policy coordination, linear quadratic differential games

A Microfounded Sectoral Model for Open Economies

In this paper we derive a microfounded macro New Keynesian model for open economies, be them large or small. We consider habit formation in consumption, sectoral linkages for tradable and non-tradable goods, capital stock investments with variable capital utilization, domestic and foreign governments, imperfect (exchange rate) pass-through in import prices and incomplete international financial markets. Sticky nominal prices and wages are modeled in Calvo and Taylor staggered ways. The model economy is composed of a continuum of infinitely-lived consumers and producers of final and intermediate goods. We provide a very general log-linearization method, from which we can easily obtain various special cases, as trend inflation or steady-state log-linearizations.Numerical simulations of the two-country sectoral model are provided for a relatively large number of structural shocks as domestic and foreign productivity shocks in final tradables and non-tradables, money demand shocks and a shock in the exchange rate. Such a model is well suited for monetary policy analysis at the international level and risk analysis.New Keynesian open economy model, tradable and non-tradable sectors, final and intermediate goods, log-linearization

HCV Lymphotropism and Its Pathogenic Significance

Hepatitis C virus (HCV) is not only a hepatotropic but also a lymphotropic virus. Infection of the immune system appears to be a natural propensity of HCV and, as the accumulated data indicate, a common characteristic of both symptomatic and clinically silent but molecularly evident infection known as occult infection. The ability of HCV to infect cells of the immune system is consistent with a significantly greater prevalence of certain lymphoproliferative disorders in HCV-infected patients, such as mixed cryoglobulinemia and B-cell non-Hodgkin’s lymphoma. This chapter recapitulates the approaches used to detect HCV and its replication within lymphoid cells, features of HCV compartmentalization in the lymphatic system and in different types of immune cells, and the cell culture models developed to study HCV lymphotropism. In addition, the characteristics of the molecules recently identified as those specifically mediating HCV entry leading to virus replication in B and T lymphocytes, which are distinct from those involved in virus entry to hepatocytes, are presented. Finally, the biological impact of HCV lymphotropism on the function of immune cells, virus persistence, and immune cell proliferation and lymphomagenesis is summarized

Exogenous coalition formation in the e-marketplace based on geographical proximity

This paper considers a model for exogenous coalition formation in e-marketplaces. Using the informational advantage e-retailer creates coalitions of customers based on geographical proximity. Most of the literature regards this process as endogenous: a coalition leader bundles eventual purchases together in order to obtain a better bargaining position. In contrast - and in response to what is being observed in business practice - we analyse a situation in which an existing e-retailer exogenously forms customers' coalitions. Results of this study are highly encouraging. Namely, we demonstrate that even under highly imperfect warehouse management schemes leading to contagion eects, suggested combined delivery service may oer signifficant efficiency gains as well as opportunities for Pareto-improvement.Coalition formation, e-commerce, multi-agent systems, consumer satisfaction, demand planning, warehouse management.

Computational Aspects of Extending the Shapley Value to Coalitional Games with Externalities

Until recently, computational aspects of the Shapley value were only studied under the assumption that there are no externalities from coalition formation, i.e., that the value of any coalition is independent of other coalitions in the system. However, externalities play a key role in many real-life situations and have been extensively studied in the game-theoretic and economic literature. In this paper, we consider the issue of computing extensions of the Shapley value to coalitional games with externalities proposed by Myerson [21], Pham Do and Norde [23], and McQuillin [17]. To facilitate efficient computation of these extensions, we propose a new representation for coalitional games with externalities, which is based on weighted logical expressions. We demonstrate that this representation is fully expressive and, sometimes, exponentially more concise than the conventional partition function game model. Furthermore, it allows us to compute the aforementioned extensions of the Shapley value in time linear in the size of the input

Matchings with externalities and attitudes

Two-sided matchings are an important theoretical tool used to model markets and social interactions. In many real-life problems the utility of an agent is influenced not only by their own choices, but also by the choices that other agents make. Such an influence is called an externality. Whereas fully expressive representations of externalities in matchings require exponential space, in this paper we propose a compact model of externalities, in which the influence of a match on each agent is computed additively. Under this framework, we analyze many-to-many matchings and one-to-one matchings where agents take different attitudes when reasoning about the actions of others. In particular, we study optimistic, neutral and pessimistic attitudes and provide both computational hardness results and polynomial-time algorithms for computing stable outcomes