10,623 research outputs found

    Review: Vidler, Laura L. Performance Reconstruction and Spanish Golden Age Drama: Reviving and Revising the Comedia

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    Review of Vidler, Laura L. Performance Reconstruction and Spanish Golden Age Drama: Reviving and Revising the Comedia. Palgrave Macmillan, 201

    Cosmological evolution of a complex scalar field with repulsive or attractive self-interaction

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    We study the cosmological evolution of a complex scalar field with a self-interaction potential V(∣φ∣2)V(|\varphi|^2), possibly describing self-gravitating Bose-Einstein condensates, using a fully general relativistic treatment. We generalize the hydrodynamic representation of the Klein-Gordon-Einstein equations in the weak field approximation developed in our previous paper. We establish the general equations governing the evolution of a spatially homogeneous complex scalar field in an expanding background. We show how they can be simplified in the fast oscillation regime and derive the equation of state of the scalar field in parametric form for an arbitrary potential. We explicitly consider the case of a quartic potential with repulsive or attractive self-interaction and determine the phase diagram of the scalar field. We show that the transition between the weakly self-interacting regime and the strongly self-interacting regime depends on how the scattering length of the bosons compares with their effective Schwarzschild radius. We also constrain the parameters of the scalar field from astrophysical and cosmological observations. Numerical applications are made for ultralight bosons without self-interaction (fuzzy dark matter), for bosons with repulsive self-interaction, and for bosons with attractive self-interaction (QCD axions and ultralight axions).Comment: 42 pages, 23 figures. Accepted for publication in Phys. Rev.

    Exact relaxation for polynomial optimization on semi-algebraic sets

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    In this paper, we study the problem of computing by relaxation hierarchies the infimum of a real polynomial function f on a closed basic semialgebraic set and the points where this infimum is reached, if they exist. We show that when the infimum is reached, a relaxation hierarchy constructed from the Karush-Kuhn-Tucker ideal is always exact and that the vanishing ideal of the KKT minimizer points is generated by the kernel of the associated moment matrix in that degree, even if this ideal is not zero-dimensional. We also show that this relaxation allows to detect when there is no KKT minimizer. We prove that the exactness of the relaxation depends only on the real points which satisfy these constraints.This exploits representations of positive polynomials as elementsof the preordering modulo the KKT ideal, which only involves polynomials in the initial set of variables. Applications to global optimization, optimization on semialgebraic sets defined by regular sets of constraints, optimization on finite semialgebraic sets, real radical computation are given

    Border Basis relaxation for polynomial optimization

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    A relaxation method based on border basis reduction which improves the efficiency of Lasserre's approach is proposed to compute the optimum of a polynomial function on a basic closed semi algebraic set. A new stopping criterion is given to detect when the relaxation sequence reaches the minimum, using a sparse flat extension criterion. We also provide a new algorithm to reconstruct a finite sum of weighted Dirac measures from a truncated sequence of moments, which can be applied to other sparse reconstruction problems. As an application, we obtain a new algorithm to compute zero-dimensional minimizer ideals and the minimizer points or zero-dimensional G-radical ideals. Experimentations show the impact of this new method on significant benchmarks.Comment: Accepted for publication in Journal of Symbolic Computatio

    La Villa de Urueña: seguimiento analítico para actuar en la conservación y restauración de su Castillo y la Muralla

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    Gobernando el borde suroeste de los Montes Torozos sobre la interminable expla-nada de Tierra de Campos descubrimos a Urueña, pequeño pueblo de gran relevancia histórica sobre los renios de Castilla y de León. La villa rodeada por una potente muralla forma junto con el castillo anexo a ella y con la ermita de la Anunciada, observada desde la almenas de este su-blime muro, un conjunto histórico artístico. El gran trabajo de Luis Cervera Vera por la recuperación y restauración de este monumento en 1971 supuso un cambio determinante para restablecer la figura de la villa y recuperar el concep-to limitador. Con este análisis se busca documentar y reencontrar los valores que envuelven al conjunto, con el fin de conservar su unidad y ampliar el uso paisajístico que encontramos en él

    On Sevillian guilds towards the end of the 11th century

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    In the third decade of the 20th century, Lévi-Provençal discovered an Arab manuscript by the ishbīlī Ibn cAbdūn, that dealt with the commercial and artisan practices in Seville at the end of the 11th century. In the document there were references to the offices and personages who had to perform certain functions in various professions. From this manuscript, Lévi-Provençal deduced the existence of 11th-century Islamic guilds in Seville. This idea was assumed by Spanish historians, even up until the final decade of the 20th century. In the present article, the basis which sustained such an idea is analyzed with particular emphasis on the treatise by Ibn cAbdūn, since this is the only work that describes the economy of Seville at the time of Classic Islam (before the 12th century), and since this is the principal historical source cited by recent historians as a guarantee of the existence of Sevillian guilds during the Classic Islam; however, other manuscripts of Islamic authors of al-Andalus, and articles of contemporary authors are also taken into account. The result of our investigation disproves the existence of 11th century Islamic guilds in SevilleEn la tercera década del siglo XX Lévi-Proveçal descubrió un manuscrito árabe del išbīlī Ibn cAbdūn, donde se tratan las prácticas comerciales y artesanales en Sevilla a finales del siglo XI. En él hay referencias a los oficios y a personajes que debían cumplir determinadas funciones sobre la profesión. De ahí Lévi-Provençal dedujo la existencia de gremios islámicos en Sevilla. Esta idea resultó ser sugestiva y fue asumida por historiadores españoles del siglo XX, incluso en la década final de ese siglo. En el presente artículo se analizan las bases que sustentaron tal idea, haciéndose especial hincapié en el Tratado de Ibn cAbdūn por ser la única obra que se refiere a la economía de Sevilla en la época del islam clásico (antes del siglo XII) y la principal fuente histórica mencionada por dichos historiadores recientes como garantía de la existencia de gremios sevillanos durante el islam; sin embargo, también se tendrán en cuenta otros manuscritos de autores islámicos de al-Andalus y artículos de autores contemporáneos. El resultado de nuestra investigación refuta la existencia de gremios islámicos en la Sevilla del siglo X
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