Fiscal harmonization in the presence of public inputs

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

Breakdown of smoothness for the Muskat problem

In this paper we show that there exist analytic initial data in the stable regime for the Muskat problem such that the solution turns to the unstable regime and later breaks down i.e. no longer belongs to $C^4$.Comment: 93 pages, 10 figures (6 added

Ricci flow, quantum mechanics and gravity

It has been argued that, underlying any given quantum-mechanical model, there exists at least one deterministic system that reproduces, after prequantisation, the given quantum dynamics. For a quantum mechanics with a complex d-dimensional Hilbert space, the Lie group SU(d) represents classical canonical transformations on the projective space CP^{d-1} of quantum states. Let R stand for the Ricci flow of the manifold SU(d-1) down to one point, and let P denote the projection from the Hopf bundle onto its base CP^{d-1}. Then the underlying deterministic model we propose here is the Lie group SU(d), acted on by the operation PR. Finally we comment on some possible consequences that our model may have on a quantum theory of gravity.Comment: 8 page

Public and private sector wages interactions in a general equilibrium model

This paper develops a dynamic general equilibrium model in which the public and the private sector interact in the labor market. Previous studies that analyze the labor market effects of public sector employment and wages have mostly assumed exogenous rules for public wage and public employment. We show that theories that equalize wages with marginal products in the private sector can rationalize the interaction of public and private sector wages when extended to accommodate a non-trivial government sector/public sector union that endogenously determines public employment and wages. Our model suggests a positive correlation between public and private sector wages. Any increase in tax revenues, coupled with the existence of a positive public-private sector wage gap, makes working in the public sector an attractive option. Thus, a positive neutral productivity shock increases public and private sector wages. More interestingly, even a private-sector specific productivity shock spills-over to the public sector, increasing public wages. These facts lend some support to the wage leading role of the private sector. Nevertheless, at the same time, a positive shock to public sector wages would lead to an increase in private sector wages, via the flow of workers from the private to the public sector. JEL Classification: C32, J30, J51, J52, E62, E63, H50Labor market, public employment, public wages, Trade Unions

Roper Excitation in Alpha-Proton Scattering

We study the Roper excitation in the $(\alpha,\alpha')$ 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 $\Delta$ 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 $NN \rightarrow NN^*$ 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

On the noncommutative eikonal

We study the eikonal approximation to quantum mechanics on the Moyal plane. Instead of using a star product, the analysis is carried out in terms of operator-valued wavefunctions depending on noncommuting, operator-valued coordinates.Comment: 18 page

The Imaginary Part of Nucleon Self-energy in hot nuclear matter

A semiphenomenological approach to the nucleon self-energy in nuclear matter at finite temperatures is followed. It combines elements of Thermo Field Dynamics for the treatment of finite temperature with a model for the self-energy, which evaluates the second order diagrams taking the needed dynamics of the NN interaction from experiment. The approach proved to be accurate at zero temperature to reproduce Im(Sigma) and other properties of nucleons in matter. In the present case we apply it to determine Im(Sigma) at finite temperatures. An effective NN cross section is deduced which can be easily used in analyses of heavy ion reactions.Comment: 15 pages, 6 postscripts figures, to be published in Nucl. Phys.

A new genus and sixteen new species of false click beetles (Coleoptera: Eucnemidae) described from the Heredia Province of Costa Rica with several additional records from the Osa Peninsula and Panama

More than 1300 specimens of Eucnemidae collected from Heredia Province in Costa Rica during the 1990s Arthropods of La Selva (ALAS) survey were studied from 2018 through 2022. One new genus of false click beetle, Absensiugum Otto, Muona and Córdoba-Alfaro, is described. Nematodes teres Horn, from the Ne­arctic and Caribbean regions, is transferred to this new genus to form Absensiugum teres, new combination. Sixteen new species of false click beetle (Coleoptera: Eucnemidae) are described from Costa Rica. These new species are: Adelothyreus brevis, Adelothyreus costaricensis, Adelothyreus totus, Quirsfeldia stethonoides, Lacus pectinatus, Maelodrus costaricensis, Onichodon confluentus, Onichodon rufus, Isarthrus striatus, Absensiugum brunneum, Dromaeolus americanus, Dromaeolus brunneus, Dromaeolus herediensis, Dromaeolus holdridgei, Deltometopus bicolor and Nematodes apicalis. Three additional records outside of the Heredia Province from the Osa Peninsula and Panama for Lacus pectinatus are included in this study. Identification keys are provided for species of Adelothyreus Chevrolat, Onichodon Newman, Dromaeolus Kiesenwetter, Deltometopus Bonvou­loir and Nematodes Berthold in Costa Rica. Diagnostic differences are briefly noted for each species within the Neotropical region. A list of Eucnemidae from Heredia Province is provided. Resumen. Se estudiaron más de 1300 especímenes de Eucnemidae recolectados de la provincia de Heredia en Costa Rica durante la encuesta de Artrópodos de La Selva (ALAS) de la década de 1990 desde 2018 hasta 2021. Se describe un nuevo género de escarabajo de falso clic, Absensiugum Otto, Muona y Córdoba-Al­faro. Nematodes teres Horn, de las regiones Neártica y Caribe, se transfiere a este nuevo género para formar Absensiugum teres, nueva combinación. Se describen dieciséis nuevas especies de escarabajos de falso clic (Coleoptera: Eucnemidae) de Costa Rica. Estas nuevas especies son: Adelothyreus brevis, Adelothyreus cos­taricensis, Adelothyreus totus, Quirsfeldia stethonoides, Lacus pectinatus, Maelodrus costaricensis, Onichodon confluentus, Onichodon rufus, Isarthrus striatus, Absensiugum brunneum, Dromaeolus americanus, Dromaeo­lus brunneus, Dromaeolus herediensis, Dromaeolus holdridgei, Deltometopus bicolor and Nematodes apicalis. En este estudio se incluyen tres registros adicionales fuera de la Provincia de Heredia de la Península de Osa y Panamá para Lacus pectinatus. Se proporcionan claves de identificación para especies de Adelothyreus Che­vrolat, Onichodon Newman, Dromaeolus Kiesenwetter, Deltometopus Bonvouloir and Nematodes Berthold en Costa Rica. Las diferencias de diagnóstico se observan brevemente para cada espec

Rank one discrete valuations of power series fields

In this paper we study the rank one discrete valuations of the field $k((X_1,..., X_n))$ whose center in k\lcor\X\rcor is the maximal ideal. In sections 2 to 6 we give a construction of a system of parametric equations describing such valuations. This amounts to finding a parameter and a field of coefficients. We devote section 2 to finding an element of value 1, that is, a parameter. The field of coefficients is the residue field of the valuation, and it is given in section 5. The constructions given in these sections are not effective in the general case, because we need either to use the Zorn's lemma or to know explicitly a section $\sigma$ of the natural homomorphism R_v\to\d between the ring and the residue field of the valuation $v$. However, as a consequence of this construction, in section 7, we prove that k((\X)) can be embedded into a field L((\Y)), where $L$ is an algebraic extension of $k$ and the {\em ``extended valuation'' is as close as possible to the usual order function}