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We introduce a Hopf algebroid associated to a proper Lie group action on a smooth manifold. We prove that the cyclic cohomology of this Hopf algebroid is equal to the de Rham cohomology of invariant differential forms. When the action is…

Differential Geometry · Mathematics 2010-02-25 Xiang Tang , Yi-Jun Yao , Weiping Zhang

This is a survey of a variety of equivariant (co)homology theories for operator algebras. We briefly discuss a background on equivariant theories, such as equivariant $K$-theory and equivariant cyclic homology. As the main focus, we discuss…

Operator Algebras · Mathematics 2019-02-12 Massoud Amini , Ahmad Shirinkalam

We introduce a parametrized version of scissors congruence $K$-theory of manifolds with tangential structure, which includes a topologized version of the scissors congruence $K$-theory of oriented manifolds as a special case. We examine the…

Algebraic Topology · Mathematics 2026-04-03 Mona Merling , George Raptis , Julia Semikina

On the generalized tangent bundle of a smooth manifold, we study skew-symmetric endomorphism satisfying an arbitrary polynomial equation with real constant coefficients. We study the compatibility of these structures with the de Rham…

Differential Geometry · Mathematics 2022-12-29 Marco Aldi , Daniele Grandini

We compute the homology of the space of equivariant loops on the classifying space of a simplicial monoid $M$ with anti-involution, provided $\pi_0 (M)$ is central in the homology ring of $M$. The proof is similar to McDuff and Segal's…

K-Theory and Homology · Mathematics 2020-11-11 Kristian Jonsson Moi

In this paper, we prove an analogue of the Jordan canonical form theorem for a class of $n$-normal operators on complex separable Hilbert spaces in terms of von Neumann's reduction theory. This is a continuation of our study of bounded…

Functional Analysis · Mathematics 2012-11-28 Chunlan Jiang , Rui Shi

Let G be a finite group acting on a finite dimensional real vector space V. We denote by P(V) the projective space associated to V. In this paper we compute in a very explicit way the rank of the equivariant complex K-theory of V and P(V),…

K-Theory and Homology · Mathematics 2007-05-23 Max Karoubi

Based on the Euler-Lagrange cohomology groups $H_{EL}^{(2k-1)}({\cal M}^{2n}) (1 \leqslant k\leqslant n)$ on symplectic manifold $({\cal M}^{2n}, \omega)$, their properties and a kind of classification of vector fields on the manifold, we…

Mathematical Physics · Physics 2007-05-23 Han-Ying Guo , Jianzhong Pan , Bin Zhou

We develop equivariant KK-theory for locally compact groupoid actions by Morita equivalences on real and complex graded C*-algebras. Functoriality with respect to generalised morphisms and Bott periodicity are discussed. We introduce…

K-Theory and Homology · Mathematics 2013-10-16 El-kaïoum M. Moutuou

We proved the convergence of a sequence of 2 dimensional comapct Kahler-Einstein orbifolds with rational quotient singularities and with some uniform bounds on the volumes and on the Euler characteristics of our orbifods to a…

Differential Geometry · Mathematics 2007-05-23 Natasa Sesum

We deduce an index jump formula for first order elliptic complexes over end-periodic manifolds, which generalizes the corresponding result for the DeRham complex. In the case of the anti-self-dual DeRham complex, we define the periodic rho…

Geometric Topology · Mathematics 2022-01-28 Langte Ma

Using the unbounded picture of analytical K-homology, we associate a well-defined K-homology class to an unbounded symmetric operator satisfying certain mild technical conditions. We also establish an ``addition formula'' for the Dirac…

K-Theory and Homology · Mathematics 2007-05-23 Hela Bettaieb , Michel Matthey , Alain Valette

A classical theorem of Frankel for compact K\"ahler manifolds states that a K\"ahler S^1-action is Hamiltonian if and only if it has fixed points. We prove a metatheorem which says that when Hodge theory holds on non-compact manifolds, then…

Symplectic Geometry · Mathematics 2015-06-18 Rafe Mazzeo , Álvaro Pelayo , Tudor Ratiu

The aim of this paper is to describe the equivariant and ordinary Grothendieck ring and the equivariant and ordinary topological $K$-ring of flag Bott manifolds of general Lie type. This will generalize the results on the equivariant and…

Algebraic Topology · Mathematics 2024-06-18 Bidhan Paul , Vikraman Uma

Let A be a separable unital nuclear purely infinite simple C*-algebra satisfying the Universal Coefficient Theorem, and such that the K_0-class of the identity is zero. We prove that every automorphism of order two of the K-theory of A is…

Operator Algebras · Mathematics 2007-05-23 David J. Benson , Alex Kumjian , N. Christopher Phillips

The category of rational O(2)-equivariant cohomology theories has an algebraic model A(O(2)), as established by work of Greenlees. That is, there is an equivalence of categories between the homotopy category of rational O(2)-equivariant…

Algebraic Topology · Mathematics 2016-08-02 David Barnes

The chiral equivariant cohomology contains and generalizes the classical equivariant cohomology of a manifold M with an action of a compact Lie group G. For any simple G, there exist compact manifolds with the same classical equivariant…

Quantum Algebra · Mathematics 2011-08-12 Andrew R. Linshaw

We consider a invariant Dirac operator D on a manifold with a proper and cocompact action of a discrete group G. It gives rise to an equivariant K-homology class [D]. We show how the index of the induced orbifold Dirac operator can be…

K-Theory and Homology · Mathematics 2007-05-23 Ulrich Bunke

We introduce a scissors congruence $K$-theory spectrum which lifts the equivariant scissors congruence groups for compact $G$-manifolds with boundary, and we show that on $\pi_0$ this is the source of a spectrum level lift of the Burnside…

Algebraic Topology · Mathematics 2025-08-18 Mona Merling , Ming Ng , Julia Semikina , Alba Sendón Blanco , Lucas Williams

Let $G$ be a compact Lie group. We prove that if $V$ and $W$ are orthogonal $G$-representations such that $V^G=W^G=\{0\}$, then a $G$-equivariant map $S(V) \to S(W)$ exists provided that $\dim V^H \leq \dim W^H$ for any closed subgroup…

Algebraic Topology · Mathematics 2018-01-09 Zbigniew Błaszczyk , Wacław Marzantowicz , Mahender Singh