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We walk out the landscape of K-theoretic Poincare Duality for finite algebras. It paves the way to get continuum Dirac operators from discrete noncommutative manifolds.

High Energy Physics - Theory · Physics 2007-05-23 Alejandro Rivero

In the study of induced bilinear systems, the classical Lie algebra rank condition (LARC) is known to be impractical since it requires computing the rank everywhere. On the other hand, the transitive Lie algebra condition, while more…

Systems and Control · Electrical Eng. & Systems 2022-03-16 Gong Cheng , Wei Zhang , Jr-Shin Li

Poincare duality lies at the heart of the homological theory of manifolds. In the presence of the action of a group it is well-known that Poincare duality fails in Bredon's ordinary, integer-graded equivariant homology. We give here a…

Algebraic Topology · Mathematics 2013-12-03 Steven R. Costenoble , Stefan Waner

The main purpose of these lecture notes is to provide a concise introduction to Lie groups, Lie algebras, and isometric and adjoint actions, aiming mostly at advanced undergraduate and graduate students. In addition, the connection between…

Differential Geometry · Mathematics 2010-08-31 Marcos M. Alexandrino , Renato G. Bettiol

This is the second in a series of papers investigating the relationship between the twisted equivariant K-theory of a compact Lie group G and the "Verlinde ring" of its loop group. We introduce the Dirac family of Fredholm operators…

Algebraic Topology · Mathematics 2012-12-10 Daniel S. Freed , Michael J. Hopkins , Constantin Teleman

This paper investigates the geometry of compact contact manifolds that are uniformized by contact Lie groups, i.e., compact manifolds that are the quotient of some Lie group G with a left invariant contact structure and a uniform lattice…

Differential Geometry · Mathematics 2015-04-29 Andre Diatta , Brendan Foreman

Let K be a compact Lie group and G its complexification. For a not necessarily reduced Stein K-space X we show that there is a complex space Z endowed with a holomorphic action of the universal complexification G of K that contains X as an…

Complex Variables · Mathematics 2007-05-23 J. Hausen , P. Heinzner

Let M be a foliated manifold and G a discrete group acting on M by diffeomorphisms mapping leaves to leaves. Then G naturally acts by automorphisms on the algebra of Heisenberg pseudodifferential operators on the foliation. Our main result…

K-Theory and Homology · Mathematics 2016-12-09 Denis Perrot , Rudy Rodsphon

In this expository article, we consider first order elliptic differential operators acting on smooth vector bundles over compact manifolds, and certain invariants derived from the analysis of these operators, namely the eta invariant} and…

Differential Geometry · Mathematics 2019-08-15 Jochen Brüning , Ken Richardson

For G a Lie group acting on a symplectic manifold $(M,\omega)$ preserving a pair of Lagrangians $L_0$, $L_1$, under certain hypotheses not including equivariant transversality we construct a G-equivariant Floer cohomology of $L_0$ and…

Symplectic Geometry · Mathematics 2021-11-09 Kristen Hendricks , Robert Lipshitz , Sucharit Sarkar

We consider a connected symplectic manifold $M$ acted on properly and in a Hamiltonian fashion by a connected Lie group $G$. Inspired to the recent paper \cite{gb2}, see also \cite{ch} and \cite{pacini}, we study Lagrangian orbits of…

Differential Geometry · Mathematics 2007-05-23 Leonardo Biliotti

In the setting of a proper, cocompact action by a locally compact, unimodular group $G$ on a Riemannian manifold, we construct equivariant spectral flow of paths of Dirac-type operators. This takes values in the $K$-theory of the group…

Operator Algebras · Mathematics 2025-02-04 Peter Hochs , Aquerman Yanes

For any compact Lie group G we discuss the relation of the equivariant Reidemeister and analytic torsion of G-manifolds with their G-CW structures.

dg-ga · Mathematics 2007-05-23 U. Bunke

We obtain a generalization, for a general compact almost complex manifold, of the well-known K\"{a}hler (or Hodge) identities for K\"{a}hler manifolds involving the commutators of the exterior differential and the Lefschetz operator and its…

Differential Geometry · Mathematics 2022-08-16 Luis Fernandez , Samuel Hosmer

Given a Lie group G, a G-manifold M, and a point b of M with compact stabilizer, we construct slices for the lifted tangent and cotangent actions at a pre-image of b in terms of a slice for the G-action on M at the point b. We interpret the…

Symplectic Geometry · Mathematics 2007-05-23 Johannes Huebschmann

This paper studies the K-homology of a crossed product of a discrete group acting smoothly on a manifold, with a better understanding of the noncommutative geometry of the crossed-product as the primary goal, and the Baum-Connes apparatus…

K-Theory and Homology · Mathematics 2019-06-04 Heath Emerson

Here, we classify Lie groups acting isometrically on compact Lorentz manifolds, and in particular we describe the geometric structure of compact homogeneous Lorentz manifolds.

Differential Geometry · Mathematics 2009-09-25 Abdelghani Zeghib

We calculate the R(G)-algebra structure on the reduced equivariant K-groups of two-dimensional spheres on which a compact Lie group G acts as involutions. In particular, the reduced equivariant K-groups are trivial if G is abelian, which…

K-Theory and Homology · Mathematics 2023-10-31 Jin-Hwan Cho , Mikiya Masuda

We construct and analyse models of equivariant cohomology for differentiable stacks with Lie group actions extending classical results for smooth manifolds due to Borel, Cartan and Getzler. We also derive various spectral sequences for the…

Algebraic Topology · Mathematics 2020-11-03 Luis Alejandro Barbosa-Torres , Frank Neumann

Let $\overline{M}=\overline{G}/\overline{H}$ be a homogeneous Riemannian manifold. Given a Lie subgroup $G\subset \overline{G}$ and a reductive decomposition of the homogeneous structure of $\overline{M}$, we analyze a canonical reductive…

Differential Geometry · Mathematics 2025-06-09 José Luis Carmona Jiménez , Marco Castrillón López