10,623 research outputs found
Review: Vidler, Laura L. Performance Reconstruction and Spanish Golden Age Drama: Reviving and Revising the Comedia
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
We study the cosmological evolution of a complex scalar field with a
self-interaction potential , 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
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
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 analÃtico para actuar en la conservación y restauración de su Castillo y la Muralla
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 artÃstico.
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 paisajÃstico que encontramos en él
On Sevillian guilds towards the end of the 11th century
In the third decade of the 20th century, Lévi-Provençal discovered an Arab manuscript by the ishbÄ«lÄ« Ibn cAbdÅ«n, 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 cAbdÅ«n, 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 iÅ¡bÄ«lÄ« Ibn cAbdÅ«n, 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 debÃan cumplir determinadas funciones sobre la profesión. De ahà 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 artÃculo se analizan las bases que sustentaron tal idea, haciéndose especial hincapié en el Tratado de Ibn cAbdÅ«n por ser la única obra que se refiere a la economÃa de Sevilla en la época del islam clásico (antes del siglo XII) y la principal fuente histórica mencionada por dichos historiadores recientes como garantÃa 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 artÃculos de autores contemporáneos. El resultado de nuestra investigación refuta la existencia de gremios islámicos en la Sevilla del siglo X
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