Multi-objective Reinforcement Learning

In this talk we present PQ-learning, a new Reinforcement Learning (RL) algorithm that determines the rational behaviours of an agent in multi-objective domainsThis work is partially funded by: grant TIN2009-14179 (Spanish Government, Plan Nacional de I+D+i) and Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. Manuela Ruiz-Montiel is funded by the Spanish Ministry of Education through the National F.P.U. Progra

The 4-girth-thickness of the complete multipartite graph

The $g$-girth-thickness $\theta(g,G)$ of a graph $G$ is the smallest number of planar subgraphs of girth at least $g$ whose union is $G$. In this paper, we calculate the $4$-girth-thickness $\theta(4,G)$ of the complete $m$-partite graph $G$ when each part has an even number of vertices.Comment: 6 pages, 1 figur

Testing a DBI model for the unification of dark matter and dark energy with Gamma-Ray Bursts

We study the range of consistency of a model based on a nonlinear scalar field Dirac-Born-Infeld action for the unification of dark matter and dark energy using Gamma-Ray Bursts at high-redshifts. We use the sample of 59 high-redshift GRBs reported by Wei (2010), calibrated at low redshifts with the Union 2 sample of SNe Ia, thus avoiding the circularity problem. In this analysis, we also include the CMB7-year data and the baryonic acoustic peak BAO. Besides, it is calculated the parameter of the equation of state $w$, the deceleration parameter $q_0$ and the redshift of the transition to the decelerate-accelerated phase $z_t$.Comment: 6 pages, to appear in Proceedings of Spanish Relativity Meeting 2011 (ERE 2011) held in Madrid, Spai

A holographic principle for the existence of parallel spinor fields and an inequality of Shi-Tam type

Suppose that $\Sigma=\partial M$ is the $n$-dimensional boundary of a connected compact Riemannian spin manifold $( M,\langle\;,\;\rangle)$ with non-negative scalar curvature, and that the (inward) mean curvature $H$ of $\Sigma$ is positive. We show that the first eigenvalue of the Dirac operator of the boundary corresponding to the conformal metric $\langle\;,\;\rangle_H=H^2\langle\;,\;\rangle$ is at least $n/2$ and equality holds if and only if there exists a parallel spinor field on $M$. As a consequence, if $\Sigma$ admits an isometric and isospin immersion $\phi$ with mean curvature $H_0$ as a hypersurface into another spin Riemannian manifold $M_0$ admitting a parallel spinor field, then \begin{equation} \label{HoloIneq} \int_\Sigma H\,d\Sigma\le \int_\Sigma \frac{H^2_0}{H}\, d\Sigma \end{equation} and equality holds if and only if both immersions have the same shape operator. In this case, $\Sigma$ has to be also connected. In the special case where $M_0=\R^{n+1}$, equality in (\ref{HoloIneq}) implies that $M$ is an Euclidean domain and $\phi$ is congruent to the embedding of $\Sigma$ in $M$ as its boundary. We also prove that Inequality (\ref{HoloIneq}) implies the Positive Mass Theorem (PMT). Note that, using the PMT and the additional assumption that $\phi$ is a strictly convex embedding into the Euclidean space, Shi and Tam \cite{ST1} proved the integral inequality \begin{equation}\label{shi-tam-Ineq} \int_\Sigma H\,d\Sigma\le \int_\Sigma H_0\, d\Sigma, \end{equation} which is stronger than (\ref{HoloIneq}) .Comment: arXiv admin note: text overlap with arXiv:1502.0408

Fiscal aspects of developing countrydebt problems and debt and debt-service reduction operations : a conceptual framework

The causes and implications of the developing country debt crisis - as well as its solution - all have an important fiscal dimension. The crisis was triggered by the widespread perception that the public sectors in many heavily indebted countries were effectively insolvent in the international environment of the early 1980s. The actual fiscal response to the resulting liquidity crisis involved increased reliance on domestic financing, the inflation tax, and the curtailment of public investment. This created adverse adjustment incentives for policymakers and resulted in credit rationing, capital flight, assumption of private external claims by the public sector, and poor domestic investment performance. Solutions involve restoring fiscal health through a combination of debt relief and efficient fiscal adjustment, aimed at mitigating the burden associated with public sector debt service and minimizing the liquidity problems facing the indebted public sector. The debt and debt-service reduction (DDSR) programs implemented so far under the Brady Plan have provided only partial solutions, closing without eliminating the gap between the face value of the external debt and the present value of prospective public sector debt service. They have done so partly by reducing the former and partly by increasing the latter. Their contribution toward easing the immediate liquidity problems of the debtors has not been encouraging. The amount of debt relief embodied in Brady Plan programs enacted so far has not in itself been sufficient to restore fiscal solvency. Better-quality fiscal adjustment could greatly help improve the situation. The most important potential contribution of such programs, then, may have been the reduction - through the policy conditionality associated with resources provided by the international financial institutions - of the secondary burden associated with the internal transfer of resources to the public sector.Banks&Banking Reform,Public Sector Economics&Finance,Environmental Economics&Policies,Economic Theory&Research,Strategic Debt Management