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Related papers: A fixed point formula and Harish-Chandra's charact…

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We generalise the Atiyah-Segal-Singer fixed point theorem to noncompact manifolds. Using $KK$-theory, we extend the equivariant index to the noncompact setting, and obtain a fixed point formula for it. The fixed point formula is the…

K-Theory and Homology · Mathematics 2018-04-04 Peter Hochs , Hang Wang

Harish-Chandra classified discrete series representations of real semisimple Lie groups by describing their characters as tempered distributions with an explicit formula on the elliptic set. His approach was inspired by Weyl's proof of the…

Representation Theory · Mathematics 2025-11-26 Dragan Miličić , Anna Romanov

We obtain an equivariant index theorem, or Lefschetz fixed-point formula, for isometries from complete Riemannian manifolds to themselves. The fixed-point set of such an isometry may be noncompact. We build on techniques developed by Roe.…

Differential Geometry · Mathematics 2024-01-10 Peter Hochs

Consider a proper, isometric action by a unimodular locally compact group $G$ on a Riemannian manifold $M$ with boundary, such that $M/G$ is compact. For an equivariant, elliptic operator $D$ on $M$, and an element $g \in G$, we define a…

Differential Geometry · Mathematics 2021-10-26 Peter Hochs , Bai-Ling Wang , Hang Wang

We consider the index problem for a wide class of nonlocal elliptic operators on a smooth closed manifold, namely differential operators with shifts induced by the action of an isometric diffeomorphism. The key to the solution is the method…

Analysis of PDEs · Mathematics 2019-01-01 Anton Savin , Elmar Schrohe , Boris Sternin

For a proper, cocompact action by a locally compact group of the form $H \times G$, with $H$ compact, we define an $H \times G$-equivariant index of $H$-transversally elliptic operators, which takes values in $KK_*(C^*H, C^*G)$. This…

K-Theory and Homology · Mathematics 2020-06-24 Peter Hochs , Hang Wang

We express the index of the Dirac operator on symplectic quotients of a Hamiltonian loop group manifold with proper moment map in terms of fixed point data.

Symplectic Geometry · Mathematics 2007-05-23 Anton Alekseev , Eckhard Meinrenken , Chris Woodward

The main goal of this paper is to obtain a formula for the T-equivariant Riemann-Roch number of certain G-spaces which are the finite dimensional models of certain infinite dimensional spaces with Hamiltonian LG-actions, here T is a maximal…

Algebraic Geometry · Mathematics 2007-05-23 Sheldon X. Chang

In this paper, we examine Lie group actions on moduli spaces (sets themselves built as quotients by group actions) and their fixed points. We show that when the Lie group is compact and connected, we obtain a linear constraint. This…

Representation Theory · Mathematics 2025-01-15 C. J. Lang

This article provides a geometric bridge between two entirely different character formulas for reductive Lie groups and answers the question posed by W.Schmid in [Sch]. A corresponding problem in the compact group setting was solved by…

Representation Theory · Mathematics 2007-05-23 Matvei Libine

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

Let $G$ be a semisimple Lie group with discrete series. We use maps $K_0(C^*_rG)\to \mathbb{C}$ defined by orbital integrals to recover group theoretic information about $G$, including information contained in $K$-theory classes not…

K-Theory and Homology · Mathematics 2019-08-14 Peter Hochs , Hang Wang

We give a cohomological formula for the index of a fully elliptic pseudodifferential operator on a manifold with boundary. As in the classic case of Atiyah-Singer, we use an embedding into an euclidean space to express the index as the…

Operator Algebras · Mathematics 2013-12-16 Paulo Carrillo Rouse , Jean-Marie Lescure , Bertrand Monthubert

In the paper we consider the theory of elliptic operators acting in subspaces defined by pseudodifferential projections. This theory on closed manifolds is connected with the theory of boundary value problems for operators violating…

Differential Geometry · Mathematics 2015-06-26 A. Yu. Savin , B. Yu. Sternin

We study a class of localized indices for the Dirac type operators on a complete Riemannian orbifold, where a discrete group acts properly, co-compactly and isometrically. These localized indices, generalizing the $L^2$-index of Atiyah, are…

Differential Geometry · Mathematics 2013-07-29 Bai-Ling Wang , Hang Wang

We study two special cases of the equivariant index defined in part I of this series. We apply this index to deformations of Spin$^c$-Dirac operators, invariant under actions by possibly noncompact groups, with possibly noncompact orbit…

Differential Geometry · Mathematics 2016-03-11 Peter Hochs , Yanli Song

We will prove the following theorems. The first theorem posits the existence of a fixed point for the actions of nilpotent Lie groups on nonpositively curved compact manifolds. The second theorem states that actions of solvable Lie groups…

Group Theory · Mathematics 2016-05-18 Mehrzad Monzavi

The Atiyah-Singer index theorem is a topological formula for the index of an elliptic differential operator. The topological index depends on a cohomology class that is constructed from the principal symbol of the operator. On contact…

Differential Geometry · Mathematics 2010-07-28 Erik van Erp

We study equivariant families of Dirac operators on the source fibers of a Lie groupoid with a closed space of units and equipped with an action of an auxiliary compact Lie group. We use the Getzler rescaling method to derive a fixed-point…

Differential Geometry · Mathematics 2024-07-23 Ahmad Reza Haj Saeedi Sadegh , Shiqi Liu , Yiannis Loizides , Jesus Sanchez

In this article I describe my recent geometric localization argument dealing with actions of NONcompact groups which provides a geometric bridge between two entirely different character formulas for reductive Lie groups and answers the…

Representation Theory · Mathematics 2007-05-23 Matvei Libine
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