442 research outputs found
Integration of twisted Dirac brackets
The correspondence between Poisson structures and symplectic groupoids,
analogous to the one of Lie algebras and Lie groups, plays an important role in
Poisson geometry; it offers, in particular, a unifying framework for the study
of hamiltonian and Poisson actions. In this paper, we extend this
correspondence to the context of Dirac structures twisted by a closed 3-form.
More generally, given a Lie groupoid over a manifold , we show that
multiplicative 2-forms on relatively closed with respect to a closed 3-form
on correspond to maps from the Lie algebroid of into the
cotangent bundle of , satisfying an algebraic condition and a
differential condition with respect to the -twisted Courant bracket. This
correspondence describes, as a special case, the global objects associated to
twisted Dirac structures. As applications, we relate our results to equivariant
cohomology and foliation theory, and we give a new description of
quasi-hamiltonian spaces and group-valued momentum maps.Comment: 42 pages. Minor changes, typos corrected. Revised version to appear
in Duke Math.
Linear and multiplicative 2-forms
We study the relationship between multiplicative 2-forms on Lie groupoids and
linear 2-forms on Lie algebroids, which leads to a new approach to the
infinitesimal description of multiplicative 2-forms and to the integration of
twisted Dirac manifolds.Comment: to appear in Letters in Mathematical Physic
Classification of Invariant Star Products up to Equivariant Morita Equivalence on Symplectic Manifolds
In this paper we investigate equivariant Morita theory for algebras with
momentum maps and compute the equivariant Picard groupoid in terms of the
Picard groupoid explicitly. We consider three types of Morita theory:
ring-theoretic equivalence, *-equivalence and strong equivalence. Then we apply
these general considerations to star product algebras over symplectic manifolds
with a Lie algebra symmetry. We obtain the full classification up to
equivariant Morita equivalence.Comment: 28 pages. Minor update, fixed typos
Morita Equivalence, Picard Groupoids and Noncommutative Field Theories
In this article we review recent developments on Morita equivalence of star
products and their Picard groups. We point out the relations between
noncommutative field theories and deformed vector bundles which give the Morita
equivalence bimodules.Comment: Latex2e, 10 pages. Conference Proceeding for the Sendai Meeting 2002.
Some typos fixe
Deformation Quantization of a Certain Type of Open Systems
We give an approach to open quantum systems based on formal deformation
quantization. It is shown that classical open systems of a certain type can be
systematically quantized into quantum open systems preserving the complete
positivity of the open time evolution. The usual example of linearly coupled
harmonic oscillators is discussed.Comment: Major update. Improved main statements. 21 page
Integration of Dirac-Jacobi structures
We study precontact groupoids whose infinitesimal counterparts are
Dirac-Jacobi structures. These geometric objects generalize contact groupoids.
We also explain the relationship between precontact groupoids and homogeneous
presymplectic groupoids. Finally, we present some examples of precontact
groupoids.Comment: 10 pages. Brief changes in the introduction. References update
Management of a pregnant woman with fibromuscular dysplasia
No abstract available
Techniques for an image space occlusion culling engine
In this work we present several techniques applied to implement an Image Space Software Occlusion Culling Engine to increase the speed of rendering general dynamic scenes with high depth complexity. This conservative culling method is based on a tiled Occlusion Map that is updated only when needed, deferring and even avoiding the expensive per pixel rasterization process. We show how the tiles become a useful way to increase the speed of visibility tests. Finally we describe how different parts of the engine were parallelized using OpenMP directives and SIMD instructions.Eje: Workshop Computación gráfica, imágenes y visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI
Integración de recursos tecnológicos de avanzada en cursos de ingeniería en sistemas de información
El proyecto que aquí se describe, denominado LATIN@UTN (Learning And Teaching In Networks at UTN)1, ha sido oportunamente presentado en el marco de la convocatoria internacional organizada por la empresa Hewlett Packard denominada: "HP 2009 Innovation in Education Grant Initiative for Latin America"2. Como resultado de dicha convocatoria, el proyecto oportunamente presentado por la UTN resultó seleccionado, lo que derivó en una donación de US 90.000 en equipamiento y U$S 10.000 en fondos en efectivo). Este proyecto también se encuentra homologado por la Secretaría de Ciencia, Tecnología y Posgrado de la UTN (Res. en trámite) Cabe aclarar al respecto, que este proyecto se constituye en una continuación del realizado entre los años 2004 y 2005 en la Facultad Regional Avellaneda de la misma Universidad denominado AMERICA@UTN3.
El principal objetivo de este proyecto consiste en la creación de un aula interactiva digital que tienda a lograr cambios significativos en el proceso de enseñanza y aprendizaje. La propuesta permitirá que los estudiantes tengan un rol más activo, interactuando con sus pares y docentes en forma sincrónica y asincrónica, aprovechando al máximo los recursos del equipamiento informático y de comunicaciones ya disponible,Red de Universidades con Carreras en Informática (RedUNCI
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