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83167250333 · May 202619922001200920172026
48 results for equivariant index theory

Generalizes Molino's theory for Riemannian foliations.

problem Studying Riemannian foliations and their properties.
method Generalization of Molino's theory with discussion of projections and equivariant basic Â-genus characters.
result Equivariant basic cohomological isomorphism for Killing foliation.

New index formula connects numerical and KK-theoretic indices.

problem Equivariant index for proper group actions on manifolds.
method Developed a trace on group conjugacy classes to relate numerical and KK-theoretic indices.
result Shows that numerical index equals KK-theoretic index under certain conditions.

The equivariant coarse index is well-understood and widely used for actions by discrete groups. We extend the definition of this index to general locally compact groups. We use a suitable notion of admissible modules over CC^*-algebras of continuous functions to obtain a meaningful index. Inspired by work by Roe, we t…

2019-02-20abs ↗pdf ↗

The study analyzes spectral asymmetry and index theory on manifolds with generalized hyperbolic cusps.

problem Analyzing spectral asymmetry and index theory on manifolds with generalized hyperbolic cusps.
method Equivariant index theorem for Dirac operators on manifolds with φ\varphi-cusps under conditions on φ\varphi.
result The cusp contribution is zero if the spectrum of the relevant Dirac operator on a hypersurface is symmetric around zero.

The construction of topological index maps for equivariant families of Dirac operators requires factoring a general smooth map through maps of a very simple type: zero sections of vector bundles, open embeddings, and vector bundle projections. Roughly speaking, a normally non-singular map is a map together with such a …

2009-08-11abs ↗pdf ↗

In this note several computations of equivariant cohomology groups are performed. For the compactly supported equivariant cohomology, the notion of infinitesimal index developed in arXiv:1003.3525, allows to describe these groups in terms of certain spaces of distributions arising in the theory of splines. The new vers…

2010-05-02abs ↗pdf ↗

In this article, we start to recall the inversion formula for the convolution with the Box spline. The equivariant cohomology and the equivariant K-theory with respect to a compact torus G of various spaces associated to a linear action of G in a vector space M can be both described using some vector spaces of distribu…

2010-12-05abs ↗pdf ↗

We study complex Chern-Simons theory on a Seifert manifold M3M_3 by embedding it into string theory. We show that complex Chern-Simons theory on M3M_3 is equivalent to a topologically twisted supersymmetric theory and its partition function can be naturally regularized by turning on a mass parameter. We find that the d…

2015-01-06abs ↗pdf ↗

Defines geometric quantization for non-compact Hamiltonian torus manifolds using index theory.

problem Geometric quantization for non-compact Hamiltonian torus manifolds.
method Deformation of Dirac operator along group orbits, localization to lattice points.
result Geometric quantization is independent of the choice of polarization.

The study proves a generic multiplicity one theorem for GG-invariant minimal hypersurfaces.

problem Proving a generic multiplicity one theorem for GG-invariant minimal hypersurfaces.
method Equivariant min-max theory and analysis of GG-homology classes.
result Shows a generic multiplicity one theorem for GG-invariant minimal hypersurfaces.

The paper generalizes index theory for periodic manifolds and proves equivalence of signatures for tori.

problem Generalizing index theory for periodic manifolds and proving signature equivalence for tori.
method Periodic index theory and spectral flow for elliptic complexes, surgery formula for singular instanton homology.
result Equivalence of signatures for essentially embedded tori and surgery formula for singular instanton homology.

This paper is our first step in establishing a de Rham model for equivariant twisted KK-theory using machinery from noncommutative geometry. Let GG be a compact Lie group, MM a compact manifold on which GG acts smoothly. For any αHG3(M,Z)α\in H^3_G (M, {\mathbb Z}) we introduce a notion of localized equivariant twisted co…

2015-04-30abs ↗pdf ↗

In this paper, for a compact Lie group action,we prove the anomaly formula and the functoriality of the equivariant Bismut-Cheeger eta forms with perturbation operators when the equivariant family index vanishes. In order to prove them, we extend the Melrose-Piazza spectral section and its main properties to the equiva…

2016-10-07abs ↗pdf ↗

The paper provides obstructions to positive scalar curvature for certain manifolds with group actions.

problem Obstructions to the existence of complete invariant metrics with positive scalar curvature.
method Callias-type index theorem applied to proper actions by locally compact groups.
result Obstructions to positive scalar curvature vanish for certain Lie group actions.

In this paper, we establish an infinitesimal equivariant index formula in the noncommutative geometry framework using Greiner's approach to heat kernel asymptotics. An infinitesimal equivariant index formula for odd dimensional manifolds is also given. We define infinitesimal equivariant eta cochains, prove their regul…

2013-07-31abs ↗pdf ↗

We show that if a countable discrete group acts properly and isometrically on a spin manifold of bounded Riemannian geometry and uniformly positive scalar curvature, then, under a suitable condition on the group action, the maximal higher index of the Dirac operator vanishes in K-theory of the maximal equivariant Roe a…

2019-05-29abs ↗pdf ↗

Researchers prove an equivariant index theorem on Euclidean space.

problem Calculating the equivariant index of the Bott-Dirac operator on R2n\mathbb{R}^{2n}.
method Continuous field of CC^*-algebras and equivariant index theorem.
result Explicit calculation of the equivariant index of the Bott-Dirac operator on R2n\mathbb{R}^{2n}.

Let TT be a circle group, and LTLT be its loop group. We hope to establish an index theory for infinite-dimensional manifolds which LTLT acts on, including Hamiltonian LTLT-spaces, from the viewpoint of KKKK-theory. We have already constructed several objects in the previous paper \cite{T}, including a Hilbert space $…

2017-09-18abs ↗pdf ↗

Let DD be a (generalized) Dirac operator on a non-compact complete Riemannian manifold MM acted on by a compact Lie group GG. Let v:M>Lie(G)v:M --> Lie(G) be an equivariant map, such that the corresponding vector field on MM does not vanish outside of a compact subset. These data define an element of KK-theory of the tran…

2000-11-27abs ↗pdf ↗

We generalise the Atiyah-Segal-Singer fixed point theorem to noncompact manifolds. Using KKKK-theory, we extend the equivariant index to the noncompact setting, and obtain a fixed point formula for it. The fixed point formula is the explicit cohomological expression from Atiyah-Segal-Singer's result. In the noncompact …

2015-12-24abs ↗pdf ↗

This paper explores topological aspects of index theory for infinite-dimensional manifolds.

problem Formulating index theory for infinite-dimensional manifolds with LT-actions.
method Introducing RKK-theory and constructing assembly maps for proper LT-spaces.
result Formulation of infinite-dimensional Poincaré duality and assembly maps.

In this paper, we prove that infinitesimal equivariant Chern-Connes characters are well-defined. We decompose an equivariant index as a pairing of infinitesimal equivariant Chern-Connes characters with the Chern character of an idempotent matrix. We compute the limit of infinitesimal equivariant Chern- Connes character…

2014-11-25abs ↗pdf ↗

In this article we extend the classical definitions of equivariant cohomotopy theory to the setting of proper actions of Lie groups. We combine methods originally developed in the analysis of nonlinear differential equations, mainly in connection with Leray-Schauder theory, and on the other hand from developments of eq…

2013-02-07abs ↗pdf ↗

Consider a proper, isometric action by a unimodular, locally compact group GG on a complete Riemannian manifold MM. For equivariant elliptic operators that are invertible outside a cocompact subset of MM, we show that a localised index in the KK-theory of the maximal group CC^*-algebra of GG is well-defined. The …

2019-09-25abs ↗pdf ↗

Constructs equivariant spectral flow for Dirac-type operators on manifolds.

problem Calculating spectral flow for Dirac-type operators on manifolds with group actions.
method Equivariant spectral flow construction for paths of Dirac-type operators on manifolds.
result Relates delocalised η-invariants and ρ-invariants for different positive scalar curvature metrics.