New age-metallicity diagnostic diagram for the Washington photometric system

The age calibration of the Washington deltaT1 index is mainly used to estimate ages of star clusters older than 1 Gyr, no age-metallicity degeneracy effect is considered. We have profusely exploited synthetic T1 versus C-T1 colour magnitude diagrams aiming at exploring the intrinsic behaviour of the deltaT1 index. The analysis shows that deltaT1 varies with age and metal content as well. In general, the dependence on age weakens for ages greater than ~ 6 Gyr, and results even less sensitive to age as the metallicity decreases. For ages younger than ~ 5 Gyr deltaT1 shows a strong correlation with both age and metallicity. The deltaC index -defined as deltaT1 for the C passband- is also a combined measurement of age and metallicity. We introduce a new age-metallicity diagnostic diagram, deltaT1 versus deltaC - deltaT1, which has shown the ability of unambiguously providing age and metallicity estimates, simultaneously. The new procedure allows to derive ages from 1 up to 13 Gyr and metallicities [Fe/H] from -2.0 up to +0.5 dex, and is independent of the cluster reddening and distance modulus. It does solve the constraints found in the deltaT1 index and surpasses the performance of the standard giant branch metallicity method. All these features make the diagnostic diagram a powerful tool for estimating accurate ages as well as metallicities.Comment: 14 pages, 7 figures, accepted for publication in MNRA

From Imitation to Prediction, Data Compression vs Recurrent Neural Networks for Natural Language Processing

In recent studies [1][13][12] Recurrent Neural Networks were used for generative processes and their surprising performance can be explained by their ability to create good predictions. In addition, data compression is also based on predictions. What the problem comes down to is whether a data compressor could be used to perform as well as recurrent neural networks in natural language processing tasks. If this is possible,then the problem comes down to determining if a compression algorithm is even more intelligent than a neural network in specific tasks related to human language. In our journey we discovered what we think is the fundamental difference between a Data Compression Algorithm and a Recurrent Neural Network

Relaciones de comedia en Cerdeña: los pliegos del taller sevillano de los Hermosilla (1648-1739) en la Biblioteca Universitaria de Cagliari

[Resumen] Este trabajo ofrece un estudio bibliográfico sobre dieciocho textos de relaciones de comedia de la Bibloteca Universitaria de Cagliari (Cerdeña) salidos del taller sevillano de Hermosilla entre los años 1685-1738, un rico y poco conocido fondo de pliegos sueltos teatrales de principios del s. XVIII, con la edición de dos piezas desconocidas.[Abstract] This paper provides a bibliographical study on eighteen texts of “relaciones de comedia” preserved in the University Library of Cagliari (Sardinia) and produced by Hermosilla Printing office at Seville between 1685-1738. It includes a bibliographical repertory of thouse broadsheets or “pliegos sueltos” at the begnining of the 18th century and the edition of two unknown pieces

Ethic, mystic and politics in Ezequiel Martínez Estrada y Leopoldo Zea

El artículo propone un ejercicio de contrapunto entre las obras de Ezequiel Martínez Estrada (Argentina, 1895-1964) y Leopoldo Zea (México, 1912-2004), centrando la atención en dos dimensiones básicas: (a) la manera de concebir el vínculo del intelectual con la política; (b) el modo de pensar las relaciones entre las esferas de lo dado, lo inminente y lo deseable. Se introducen las siguientes hipótesis descriptivas: 1) Con respecto al ámbito de lo dado, en ambos casos se asiste a una estimación crítica del mismo que, en términos de auto-percepción, gravita hacia una identificación con las figuras del terapeuta y del predicador; 2) En relación con la esfera de lo deseable, se identifica en ambas obras un movimiento orientado, de un lado, a combinar un innegable afán de modernidad con una también innegable fascinación por realidades y lógicas tipo Gemeinschaft y, del otro, a preservar cierta tensión relacionada con el plano de lo trascendente; 3) Dicho movimiento ostenta acentos específicos en cada caso, quedando asociado a motivos simbólicos e implicaciones prácticas dispares.Fil: Kozel, Gabriel Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Darcy Ribeiro y el concepto de civilización

Estudio de los usos del concepto de civilización en la obra del antropólogo, educador, ensayista, novelista y político brasileño Darcy Ribeiro (1922-1997). El tema ofrece varias aristas de interés. Una concierne al esclarecimiento de la presencia y las modulaciones de un término clave en la obra de un pensador clásico, lo cual invita a su vez a reflexionar sobre una serie de procesos relevantes para los estudios de las ideas: condiciones de ideación, escritura y circulación; procesos de asimilación, bricolaje y creación intelectual; perdurabilidades, inestabilidades y deslizamientos de los núcleos temáticos y axiológicos; relaciones entre las esferas política e intelectual; papel de los exilios y viajes, entre otros. Otra arista de interés remite a la posibilidad de enriquecer el enfoque civilizacional en cuanto que vía disponible para pensar la especificidad de la cultura latinoamericana.Study of how the concept of civilization was used by Brazilian anthropologist, educator, essayist, novelist, and politician Darcy Ribeiro (1922-1997). By presenting a key term and its development in the work of a classic thinker, we’ll reflect upon a series of processes relevant to the studies of ideas: the conditions for thinking, writing, and spreading of ideas; the processes of intellectual creation, assimilation, and amalgamation; instances of adherence, instability and estrangement from the thematic and axiological basis; interactions of the political and the intellectual spheres; influences from exile and journeys. Assessment of Darcy Ribeiro’s contributions to the civilizational approach with the specificities of Latin-American culture in mind.Fil: Kozel, Gabriel Andrés. Universidad Nacional de San Martin. Escuela de Humanidades. Centro de Estudios Latinoamericanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Metric geometry of infinite dimensional Lie groups and their homogeneous spaces

We study the geometry of Lie groups G with a continuous Finsler metric, in presence of a subgroup K such that the metric is right-invariant for the action of K. We present a systematic study of the metric and geodesic structure of homogeneous spaces M obtained by the quotient M≃G/K. Of particular interest are left-invariant metrics of G which are then bi-invariant for the action of K. We then focus on the geodesic structure of groups K that admit bi-invariant metrics, proving that one-parameter groups are short paths for those metrics, and characterizing all other short paths. We provide applications of the results obtained, in two settings: manifolds of Banach space linear operators, and groups of maps from compact manifolds.Fil: Larotonda, Gabriel Andrés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

Nonpositive Curvature: A Geometric Approach to Hilbert-Schmidt Operators

We give a Riemannian structure to the set Σ of positive invertible unitized Hilbert–Schmidt operators, by means of the trace inner product. This metric makes of Σ a nonpositively curved, simply connected and metrically complete Hilbert manifold. The manifold Σ is a universal model for symmetric spaces of the noncompact type: any such space can be isometrically embedded into Σ. We give an intrinsic algebraic characterization of convex closed submanifolds M. We study the group of isometries of such submanifolds: we prove that GM, the Banach–Lie group generated by M, acts isometrically and transitively on M. Moreover, GM admits a polar decomposition relative to M, namely GM M × K as Hilbert manifolds (here K is the isotropy of p = 1 for the action Ig :p → gpg∗), and also GM/K M so M is an homogeneous space. We obtain several decomposition theorems by means of geodesically convex submanifolds M. These decompositions are obtained via a nonlinear but analytic orthogonal projection ΠM :Σ → M, a map which is a contraction for the geodesic distance. As a byproduct, we prove the isomorphism NM Σ (here NM stands for the normal bundle of a convex closed submanifold M). Writing down the factorizations for fixed ea, we obtain ea = ex evex with ex ∈ M and v orthogonal to M at p = 1. As a corollary we obtain decompositions for the full group of invertible elements G M × exp(T1M⊥) × K.Fil: Larotonda, Gabriel Andrés. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderon; Argentin

The case of equality in Young's inequality for the s-numbers in semi-finite von Neumann algebras

For a semi-finite von Neumann algebra A, we study the case of equality in Young´s inequality of s-numbers for a pair of τ-measurable operators a,b, and we prove that equality is only possible if |a|^p=|b|^q. We also extend the result to unbounded operators affiliated with A, and relate this problem with other symmetric norm Young inequalities.Fil: Larotonda, Gabriel Andrés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

Inequalities related to Bourin and Heinz means with a complex parameter

A conjecture posed by S. Hayajneh and F. Kittaneh claims that given A, B positive matrices, 0≤t≤1, and any unitarily invariant norm the following inequality holds{triple vertical-rule fence}AtB1-t+BtA1-t{triple vertical-rule fence}≤{triple vertical-rule fence}AtB1-t+A1-tBt{triple vertical-rule fence}. Recently, R. Bhatia proved the inequality for the case of the Frobenius norm and for t∈[14,34]. In this paper, using complex methods we extend this result to complex values of the parameter t=z in the strip {z∈C:Re(z)∈[14,34]}. We give an elementary proof of the fact that equality holds for some z in the strip if and only if A and B commute. We also show a counterexample to the general conjecture by exhibiting a pair of positive matrices such that the claim does not hold for the uniform norm. Finally, we give a counterexample for a related singular value inequality given by s(AtB1-t+BtA1-t)≤sj(A+B), answering in the negative a question made by K. Audenaert and F. Kittaneh. The methods of proof and examples can be adapted with no modifications to operator algebras (infinite dimensional setting), for instance it follows that the inequality above holds for Hilbert-Schmidt operators with their Banach algebra norm derived from the infinite trace of B(H).Fil: Bottazzi, Tamara Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Elencwajg, René. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Larotonda, Gabriel Andrés. Universidad Nacional de General Sarmiento; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Varela, Alejandro. Universidad Nacional de General Sarmiento; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin