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We compute the equivariant index of the twisted horizontal Dolbeault operator on compact toric contact manifolds of Reeb type. The operator is elliptic transverse to the Reeb foliation and its equivariant index defines a distribution on the…

Differential Geometry · Mathematics 2023-06-28 Pedram Hekmati , Marcos Orseli

T.-J. Li and W. Zhang defined an almost complex structure $J$ on a manifold $X$ to be {\em \Cpf}, if the second de Rham cohomology group can be decomposed as a direct sum of the subgroups whose elements are cohomology classes admitting…

Symplectic Geometry · Mathematics 2012-11-13 Richard Hind , Costantino Medori , Adriano Tomassini

For manifolds equipped with group actions, we have the following natural question: To what extent does the equivariant cohomology determine the equivariant diffeotype? We resolve this question for Hamiltonian circle actions on compact,…

Symplectic Geometry · Mathematics 2024-12-20 Tara S. Holm , Liat Kessler , Susan Tolman

We study $\mathcal D$-homothetic deformations of almost $\alpha$-Kenmotsu structures. We characterize almost contact metric manifolds which are $CR$-integrable almost $\alpha$-Kenmotsu manifolds, through the existence of a canonical linear…

Differential Geometry · Mathematics 2010-06-25 Giulia Dileo

We compute the cyclic homology for the cross-product al- gebra $A(M)\rtimes\Gamma$ of the algebra of complete symbols on a compact man- ifold $M$ with action of a finite group $\Gamma$. A spectral sequence argument shows that these groups…

K-Theory and Homology · Mathematics 2010-05-14 Shantanu Dave

This is primarily an expository note showing that earlier work of Lai on CR geometry provides a clean interpretation, in terms of a Gauss map, for an adjunction formula for embedded surfaces in an almost complex four manifold. We will see…

Differential Geometry · Mathematics 2007-05-23 Mikhail Chkhenkeli , Thomas Garrity

We consider a class of homogeneous manifolds including all semisimple coadjoint orbits. We describe manifolds of that class admitting deformation q uantizations equivariant under the action of $G$ and the corresponding quantum group. We…

Quantum Algebra · Mathematics 2009-11-07 Joseph Donin , Vadim Ostapenko

We prove a formula for the multiplicities of the index of an equivariant transversally elliptic operator on a $G$-manifold. The formula is a sum of integrals over blowups of the strata of the group action and also involves eta invariants of…

Differential Geometry · Mathematics 2010-07-21 Jochen Bruening , Franz Kamber , Ken Richardson

Let $\gp$ be a finite group acting on a compact manifold $M$ and $\maA(M)$ denote the algebra of classical complete symbols on $M$. We determine all traces on the cross-product algebra $\maA(M) \rtimes \Gamma$. These traces appear as…

Analysis of PDEs · Mathematics 2007-05-23 Shantanu Dave

Let $M$ be complex projective manifold and $A$ a positive line bundle on it. Assume that a compact and connected Lie group $G$ acts on $M$ in a Hamiltonian and holomorphic manner and that this action linearizes to $A$. Then, there is an…

Symplectic Geometry · Mathematics 2021-11-19 Andrea Galasso

Starting from a cubic form, we give a general construction of a quasi-complete homogeneous manifold endowed with a natural contact structure. We show that it can be compactified into a projective contact manifold if and only if the cubic…

Algebraic Geometry · Mathematics 2008-12-22 Jun-Muk Hwang , Laurent Manivel

We formulate, for any Lie group G acting isometrically on a manifold M, the general notion of a G-equivariant elliptic operator that is invertible outside of a G-cocompact subset of M. We prove a version of the Rellich lemma for this…

Differential Geometry · Mathematics 2024-09-02 Hao Guo

In this paper, we analyse the question of existence of a natural and projectively equivariant symbol calculus, using the theory of projective Cartan connections. We establish a close relationship between the existence of such a natural…

Differential Geometry · Mathematics 2007-05-23 P. Mathonet , F. Radoux

Let G be a compact Lie group and A(G) its Burnside Ring. For a compact smooth n-dimensional G-manifold X equipped with a generic G-invariant vector field v, we prove an equivariant analog of the Morse formula Ind^G(v) = \sum_{k = 0}^{n}…

Geometric Topology · Mathematics 2008-08-01 Gabriel Katz

Let G be a Lie group with finitely many connected components and let K be a maximal compact subgroup. We assume that G satisfies the rapid decay (RD) property and that G/K has non-positive sectional curvature. As an example, we can take G…

K-Theory and Homology · Mathematics 2019-12-18 Paolo Piazza , Hessel Posthuma

This is the third of a series of papers on a new equivariant cohomology that takes values in a vertex algebra, and contains and generalizes the classical equivariant cohomology of a manifold with a Lie group action a la H. Cartan. In this…

Differential Geometry · Mathematics 2021-05-21 Bong H. Lian , Andrew R. Linshaw , Bailin Song

We define an $S^1$-equivariant index for non-compact symplectic manifolds with Hamiltonian $S^1$-action. We use the perturbation by Dirac-type operator along the $S^1$-orbits. We give a formulation and a proof of quantization conjecture for…

Symplectic Geometry · Mathematics 2018-01-12 Hajime Fujita

In this note we present a formula for the equivariant index of the cohomological complex obtained from localization of $\mathcal{N}=2$ SYM on simply-connected compact four-manifolds with a $T^2$-action. Knowledge of said index is essential…

High Energy Physics - Theory · Physics 2022-09-20 Roman Mauch , Lorenzo Ruggeri

Given a non compact semisimple Lie group $G$ we describe all homogeneous spaces $G/L$ carrying an invariant almost K\"ahler structure $(\omega,J)$. When $L$ is abelian and $G$ is of classical type, we classify all such spaces which are…

Differential Geometry · Mathematics 2018-12-07 Dmitri V. Alekseevsky , Fabio Podestà

Let $B$ denote the upper triangular subgroup of $SL_2(C)$, $T$ its diagonal torus and $U$ its unipotent radical. A complex projective variety $Y$ endowed with an algebraic action of $B$ such that the fixed point set $Y^U$ is a single point,…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion , James B. Carrell