937 research outputs found

    Quantum Dynamics on the Worldvolume from Classical su(n) Cohomology

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    A key symmetry of classical pp-branes is invariance under worldvolume diffeomorphisms. Under the assumption that the worldvolume, at fixed values of the time, is a compact, quantisable K\"ahler manifold, we prove that the Lie algebra of volume-preserving diffeomorphisms of the worldvolume can be approximated by su(n)su(n), for nn\to\infty. We also prove, under the same assumptions regarding the worldvolume at fixed time, that classical Nambu brackets on the worldvolume are quantised by the multibrackets corresponding to cocycles in the cohomology of the Lie algebra su(n)su(n).Comment: This is a contribution to the Special Issue on Deformation Quantization, published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

    Fiscal harmonization in the presence of public inputs

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    Fiscal harmonization for the European Union member states is a goal that encounters major difficulties for its implementation. Each country faces a particular trade-off between fiscal revenues generated by taxation and the productive efficiency loss induced by their respective tax code. Countries for which a particular harmonized tax code requires more taxation will have to face an increased efficiency loss, whereas those required to decrease their taxes will have to face a loss in fiscal revenue. This paper provides a quantitative measure of these trade-offs, for a number of taxes and for the European Union member states, using a DGE model with public inputs. Calibration of the model for the EU-15 member states gives us the following results: i) The maximum tax revenue level is not far away from the current tax levels for most countries, ii) The cases of Sweden, Denmark and Finland are anomalous, as productive efficiency can be gained by lowering tax rates without affecting fiscal revenues, iii) In general, countries would obtain efficiency gains without changing fiscal revenues by reducing the capital tax and increasing the labor tax and iv) Capital tax harmonization to the average capital tax rate can be done with quite small changes in both fiscal revenues and output for the majority of countries.Fiscal harmonization, applied general equilibrium

    The current financial crisis: what should we learn from the great depressions of the Twentieth Century?

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    Studying the experience of countries that have experienced great depressions during the twentieth century teaches us that massive public interventions in the economy to maintain employment and investment during a financial crisis can, if they distort incentives enough, lead to a great depression.

    Union Games: Technological Unemployment

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    Given a production economy, we define a trade union game by considering strategic behavior on factor supplies. We refer to the Nash equilibria of this game as trade union equilibria. First we analyze situations under which unemployment of factors are supported as trade union equilibria. The degree of unemployment depends on technological conditions. In this line, we suggest a source of unemployment which differs from the usual sources provided in the related literature. Then, we state a limit result which shows that when the market power of trade unions decreases the corresponding sequence of trade union equilibria converges to the walrasian equilibrium, that is, to full employment of factors.Trade Union Games, unemployment, walrasian equilibrium, manipulability.

    Public debt frontiers: The greek case

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    Las causas de la crisis de deuda Griega son otras distintas de la indisciplina fiscal. Los indicadores macroeconómicos desde el año 200 a 2006 no indicaban nada que pudiera presagiar el desastre. Causas de tipo estratégico en el manejo de la deuda parecen más razonables a la hora de explicar el fenómenoUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Public Debt Frontiers: The Greek Case

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    This paper attempts to quantify the maximum amount of debt that a government can sustain by itself, i.e., the limits to public indebtedness. Using a Dynamic General Equilibrium model where the government is fully characterized, we compute the steady state inverse relationship between the public debt to output ratio and the size of the government, measured as the total public expenditures to output ratio. This line is the budget constraint of a government in steady state. Calibration of the model for the Greek economy to fiscal targets reveals that, for the period just before the current recession, i.e. 2002-2006, the debt to GDP ratio was very close to the calculate limits wich depends dramatically on the interest rates. However, short after de financial crisis of 2008, sustained deficits drove the Greek economy to a point where the Greek Government crossed the debt limit where the country could only meet its debt obligations only if international investors where willing to lend. We conclude that the hight initial level of debts previous the crisis together with the rise in interest rates were the causes of the posterior debt crisis.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Roper Excitation in Alpha-Proton Scattering

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    We study the Roper excitation in the (α,α)(\alpha,\alpha') reaction. We consider all processes which may be relevant in the Roper excitation region, namely, Roper excitation in the target, Roper excitation in the projectile, and double Δ\Delta excitation processes. The theoretical investigation shows that the Roper excitation in the proton target mediated by an isoscalar exchange is the dominant mechanism in the process. We determine an effective isoscalar interaction by means of which the experimental cross section is well reproduced. This should be useful to make predictions in related reactions and is a first step to construct eventually a microscopic NNNNNN \rightarrow NN^* transition potential, for which the present reaction does not offer enough information.Comment: Latex 17 pages; figures available by request; Phys. Rev. C in prin

    Creación de Interfaces Gráficas de Usuario (GUI) con MatLab

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    El objetivo de esta guía es aprender a realizar interfaces gráficas de usuario, a las que nos referiremos como GUI-s que es como se normalmente se conocen. El lenguaje más habitual para crear GUI-s es Java, ya que tiene la enorme ventaja de funcionar en cualquier máquina, sin embargo Ja va resulta muy lenta para hacer cálculos eficientemente, y es aquí donde MatLab es más poderoso. Por otro lado, las GUI-s creadas con MatLab pueden ser entregadas al ordenador del cliente (quien posiblemente no tenga más que un nave gador) y ser ejecutadas en el ordenador de quien creó la interfaz en MatLab (y que por supuesto tie ne un MatLab funcionando), de modo que la ventaja relativa de Java esta parcialmente ofertada también por MatLab. Las GUI-s son herramientas muy útiles para entregar aplicaciones a aquellas personas que no saben lo suficiente de programación y que quieren beneficiarse de las ventajas de un program

    Biografía del Doctor don Francisco Solano de Luque (El Pulsista) y juicio crítico de sus obras

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    Copia digital : Diputación de Málaga. Biblioteca Canovas del Castillo, 2015Premios: Trabajo premiado por la Real Sociedad Económica Cordobesa en los Juegos Florales de 1903
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