نتایج جستجو برای: groupoid

تعداد نتایج: 1035  

2009
PAUL BRESSLER

In this paper we consider deformations of an algebroid stack on an étale groupoid. We construct a differential graded Lie algebra (DGLA) which controls this deformation theory. In the case when the algebroid is a twisted form of functions we show that this DGLA is quasiisomorphic to the twist of the DGLA of Hochschild cochains on the algebra of functions on the groupoid by the characteristic cl...

2002
Bernardo Uribe

The purpose of this paper is to introduce the notion of loop groupoid LG associated to a groupoid G. After studying the general properties of LG, we show how this notion provides a very natural geometric interpretation for the twisted sectors of an orbifold [7], and for the inner local systems introduced by Ruan [14] by means of a natural generalization of the concept holonomy of a gerbe.

Journal: :Applied Categorical Structures 2003
Nick D. Gilbert

We study the structure of the flow monoid of a regular semigroup. This arises from the approach of Nambooripad of considering a regular semigroup as a groupoid – a category in which every morphism is invertible. A flow is then a section to the source map in this groupoid, and the monoid structure of the set of all flows is determined in terms of the Green relations on the original semigroup.

2003
David Pask John Quigg Iain Raeburn

k-graphs are higher-rank analogues of directed graphs which were first developed to provide combinatorial models for operator algebras of Cuntz– Krieger type. Here we develop a theory of the fundamental groupoid of a kgraph, and relate it to the fundamental groupoid of an associated graph called the 1-skeleton. We also explore the failure, in general, of k-graphs to faithfully embed into their ...

2012
JEAN RENAULT

This is a study of derivations constructed from conditionally negative type functions on groupoids which illustrates Sauvageot’s theory of noncommutative Dirichlet forms.

Journal: :Acta crystallographica. Section A, Foundations of crystallography 2006
Cyril Cayron

Daughter crystals in orientation relationship with a parent crystal are called variants. They can be created by a structural phase transition (Landau or reconstructive), by twinning or by precipitation. Internal and external classes of transformations defined from the point groups of the parent and daughter phases and from a transformation matrix allow the orientations of the distinct variants ...

2006
JEAN-LOUIS TU

We show that Haefliger’s cohomology for étale groupoids, Moore’s cohomology for locally compact groups and the Brauer group of a locally compact groupoid are all particular cases of sheaf (or Čech) cohomology for topological simplicial spaces.

2008
Thomas Timmermann

We propose a definition of compact quantum groupoids in the setting of C -algebras, associate to such a quantum groupoid a regular C -pseudo-multiplicative unitary, and use this unitary to construct a dual Hopf C -bimodule and to pass to a measurable quantum groupoid in the sense of Enock and Lesieur. Moreover, we discuss examples related to compact and to étale groupoids and study principal co...

Journal: :Int. J. Math. Mathematical Sciences 2010
Alberto S. Cattaneo Benoit Richard Umbert Dherin Giovanni Felder

the Lagrangian submanifolds of M k × M via symplectic reduction. If M is also a symplectic groupoid, then its multiplication space is an associative product in this operad. Following this idea, we provide a deformation theory for symplectic groupoids analog to the deformation theory of algebras. It turns out that the semiclassical part of Kontsevich’s deformation of C∞ d is a deformation of the...

2009
ARI STERN

We present a discrete analog of the recently introduced Hamilton– Pontryagin variational principle in Lagrangian mechanics. This unifies two, previously disparate approaches to discrete Lagrangian mechanics: either using the discrete Lagrangian to define a finite version of Hamilton’s action principle, or treating it as a symplectic generating function. This is demonstrated for a discrete Lagra...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید