English
Related papers

Related papers: A fixed point theorem on noncompact manifolds

200 papers

We describe how Lie groupoids are used in singular analysis, index theory and non-commutative geometry and give a brief overview of the theory. We also expose groupoid proofs of the Atiyah-Singer index theorem and discuss the Baum-Connes…

Operator Algebras · Mathematics 2017-05-16 Karsten Bohlen

A geometric model for twisted $K$-homology is introduced. It is modeled after the Mathai-Melrose-Singer fractional analytic index theorem in the same way as the Baum-Douglas model of $K$-homology was modeled after the Atiyah-Singer index…

K-Theory and Homology · Mathematics 2017-10-17 Robin J. Deeley , Magnus Goffeng

In this paper we explain how Morse theory for the Yang-Mills functional can be used to prove an analogue, for surface groups, of the Atiyah-Segal theorem. Classically, the Atiyah-Segal theorem relates the representation ring R(\Gamma) of a…

Algebraic Topology · Mathematics 2018-05-09 Daniel A. Ramras

We give a formulation of a deformation of Dirac operator along orbits of a group action on a possibly non-compact manifold to get an equivariant index and a K-homology cycle representing the index. We apply this framework to non-compact…

Differential Geometry · Mathematics 2021-03-02 Hajime Fujita

We have been studying the index theory for some special infinite-dimensional manifolds with a "proper cocompact" actions of the loop group LT of the circle T, from the viewpoint of the noncommutative geometry. In this paper, we will…

K-Theory and Homology · Mathematics 2022-06-22 Doman Takata

When a torus acts on a compact oriented manifold with isolated fixed points, the equivariant localization formula of Atiyah--Bott--Berline--Vergne converts the integral of an equivariantly closed form to a finite sum over the fixed points,…

Algebraic Topology · Mathematics 2013-05-21 Loring W. Tu

It is well known that elliptic operators on a smooth compact manifold are classified by K-homology. We prove that a similar classification is also valid for manifolds with simplest singularities: isolated conical points and fibered…

Operator Algebras · Mathematics 2007-05-23 A. Savin

We use $KKM$ theorem to prove the existence of a new fixed point theorem for non-expansive mapping:Let M be a bounded closed convex subset of Hilbert space H, and $A:M\rightarrow M$ be a non-expansive mapping, then exists a fixed point of A…

Functional Analysis · Mathematics 2012-08-07 Chunyan Yang

In [Wu], the noncommutative Atiyah-Patodi-Singer index theorem was proved. In this paper, we extend this theorem to the equivariant case.

Differential Geometry · Mathematics 2007-05-23 Yong Wang

In this paper, we discuss characterizations of common fixed points of commutative semigroups of nonexpansive mappings. We next prove convergence theorems to a common fixed point. We finally discuss nonexpansive retractions onto the set of…

Functional Analysis · Mathematics 2007-05-23 T. Suzuki

Consider a proper cocompact CAT(0) space X. We give a complete algebraic characterisation of amenable groups of isometries of X. For amenable discrete subgroups, an even narrower description is derived, implying Q-linearity in the…

Group Theory · Mathematics 2014-05-15 Pierre-Emmanuel Caprace , Nicolas Monod

We compare different algebraic structures in twisted equivariant K-Theory for proper actions of discrete groups. After the construction of a module structure over untwisted equivariant K-Theory, we prove a completion Theorem of Atiyah-Segal…

K-Theory and Homology · Mathematics 2019-01-15 Noe Barcenas , Mario Velasquez

Let $\Gamma$ be a finitely generated discrete group acting properly and cocompactly on a smooth manifold M. By employing heat-kernel techniques we prove a geometric formula for the pairing of the index class associated to a…

Differential Geometry · Mathematics 2025-12-17 Paolo Piazza , Hessel Posthuma , Yanli Song , Xiang Tang

Spectral triples for nonunital algebras model locally compact spaces in noncommutative geometry. In the present text, we prove the local index formula for spectral triples over nonunital algebras, without the assumption of local units in…

Operator Algebras · Mathematics 2013-01-21 A. Carey , V. Gayral , A. Rennie , F. Sukochev

We investigate the homological ideal $\mathfrak{J}_G^H$, the kernel of the restriction functors in compact Lie group equivariant Kasparov categories. Applying the relative homological algebra developed by Meyer and Nest, we relate the…

K-Theory and Homology · Mathematics 2015-12-23 Yuki Arano , Yosuke Kubota

In this paper, for a finite group, we discuss a method for calculating equivariant homology with constant coefficients. We apply it to completely calculate the geometric fixed points of the equivariant spectrum representing equivariant…

Algebraic Topology · Mathematics 2020-11-24 Sophie Kriz

Using projective spaces as examples of toric manifolds, we examine K-theoretic fixed point localization. On the one hand, we will see how the permutation-equivariant theory of the point target space emerges as a necessary ingredient. On the…

Algebraic Geometry · Mathematics 2015-08-19 Alexander Givental

The principal result of this note is the existence of a complex topological orientation for Atiyah-Segal $\mathbb{T}$-equivariant K-theory which indexes the projective space of lines in complex (n+1)-space by the Fourier expansion $1 + q +…

K-Theory and Homology · Mathematics 2025-06-19 J Morava

In this article we study cohomology of a group with coefficients in representations on Banach spaces and its stability under deformations. We show that small, metric deformations of the representation preserve vanishing of cohomology. As…

Group Theory · Mathematics 2014-09-03 Uri Bader , Piotr W. Nowak

We establish a fixed point property for a certain class of locally compact groups, including almost connected Lie groups and compact groups of finite abelian width, which act by simplicial isometries on finite rank buildings with measurable…

Group Theory · Mathematics 2013-10-04 Timothée Marquis