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Related papers: Equivariant cohomology of K-contact manifolds

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For closed manifolds with compact Lie group actions, we study Austin-Braam's Morse-theoretic construction of Borel equivariant cohomology using the technique of stabilization. We show that a $C^1$-small equivariant perturbation produces…

Differential Geometry · Mathematics 2026-01-23 Erkao Bao , Robi Huq , Shengzhen Ning

We generalize the property of small-torus equivariant K-homology of the affine Grassmannian to general oriented (co)homology theory in the sense of Levine and Morel. The main tool we use is the formal affine Demazure algebra associated to…

Algebraic Geometry · Mathematics 2023-01-31 Changlong Zhong

In this present paper we study geometry of compact complex manifolds equipped with a \emph{maximal} torus $T=(S^1)^k$ action. We give two equivalent constructions providing examples of such manifolds given a simplicial fan $\Sigma$ and a…

Complex Variables · Mathematics 2020-09-04 Yury Ustinovskiy

Let $\mathcal F$ be a co-oriented $C^2$ foliation on a closed, oriented 3-manifold. We show that $T\mathcal F$ can be perturbed to a contact structure with Reeb flow transverse to $\mathcal F$ if and only if $\mathcal F$ does not support an…

Geometric Topology · Mathematics 2024-12-25 Jonathan Zung

By the work of Li, a compact co-K\"ahler manifold $M$ is a mapping torus $K_\varphi$, where $K$ is a K\"ahler manifold and $\varphi$ is a Hermitian isometry. We show here that there is always a finite cyclic cover $\bar M$ of the form $\bar…

Differential Geometry · Mathematics 2013-04-25 Giovanni Bazzoni , John Oprea

A torus manifold is a closed smooth manifold of dimension $2n$ having an effective smooth $T^n = (S^1)^n$-action with non-empty fixed points. Petrie \cite{petrie:1973} has shown that any homotopy equivalence between a complex projective…

Algebraic Topology · Mathematics 2012-09-03 Suyoung Choi

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 study the manifold $Q_{\Gamma, \lambda}$ of isospectral real skew-symmetric matrices with a prescribed sparsity pattern determined by a graph $\Gamma$. The compact torus $T^n$ acts naturally on $Q_{\Gamma,\lambda}$ by conjugation, and…

Algebraic Topology · Mathematics 2026-02-10 Evgeny Zhukov

Let G be a group and let M be a CAT(0) proper metric space (e.g. a simply connected complete Riemannian manifold of non-positive sectional curvature or a locally finite tree). Isometric actions of G on M are (by definition) points in the…

Group Theory · Mathematics 2007-05-23 Robert Bieri , Ross Geoghegan

We prove that for a $C^\infty$-generic contact form defining a given co-oriented contact structure on a closed $3$-manifold, every hyperbolic periodic Reeb orbit admits a transverse homoclinic connection in each of the branches of its…

Symplectic Geometry · Mathematics 2025-01-22 Vincent Colin , Umberto Hryniewicz , Ana Rechtman

Let $M$ be a symplectic toric manifold acted on by a torus $\mathbb{T}$. In this work we exhibit an explicit basis for the equivariant K-theory ring $\mathcal{K}_{\mathbb{T}}(M)$ which is canonically associated to a generic component of the…

Symplectic Geometry · Mathematics 2015-03-17 Milena Pabiniak , Silvia Sabatini

Let G be a countable discrete group and let M be a smooth proper cocompact G-manifold without boundary. The Euler operator defines via Kasparov theory an element, called the equivariant Euler class, in the equivariant K-homology of M. The…

K-Theory and Homology · Mathematics 2014-11-11 Wolfgang Lueck , Jonathan Rosenberg

We study topological quivers $Q$ admitting a free and proper action by a locally compact group $G$ together with their associated $C^*$-algebras. On the topological side, we provide a complete classification of topological quivers which…

Operator Algebras · Mathematics 2025-03-21 Matthew Gillespie , Lucas Hall , Benjamin Jones , Mariusz Tobolski

Let $X$ be 2n-dimensional compact manifold with a locally standard action of a compact torus. The orbit space $X/T$ is a manifold with corners. Suppose that all proper faces of $X/T$ are acyclic. In the paper we study the homological…

Algebraic Topology · Mathematics 2014-05-20 Anton Ayzenberg

Torus orbifolds are topological generalization of symplectic toric orbifolds. We give a construction of smooth orbifolds with torus actions whose boundary is a disjoint union of torus orbifolds using toric topological method. As a result,…

Algebraic Topology · Mathematics 2019-05-21 Soumen Sarkar , Dong Youp Suh

Let X be a "nice" space with an action of a torus T. We consider the Atiyah-Bredon sequence of equivariant cohomology modules arising from the filtration of X by orbit dimension. We show that a front piece of this sequence is exact if and…

Algebraic Topology · Mathematics 2014-10-24 Christopher Allday , Matthias Franz , Volker Puppe

Let a compact torus $T=T^{n-1}$ act on an orientable smooth compact manifold $X=X^{2n}$ effectively, with nonempty finite set of fixed points, and suppose that stabilizers of all points are connected. If $H^{odd}(X)=0$ and the weights of…

Algebraic Topology · Mathematics 2026-02-10 Anton Ayzenberg , Mikiya Masuda

We describe the cohomology of the quotient Z_K/H of a moment-angle complex Z_K by a freely acting subtorus H in T^m by establishing a ring isomorphism of H*(Z_K/H,R) with an appropriate Tor-algebra of the face ring R[K], with coefficients…

Algebraic Topology · Mathematics 2015-11-30 Taras Panov

We study the existence of multiple closed Reeb orbits on some contact manifolds by means of $S^1$-equivariant symplectic homology and the index iteration formula. It is proved that a certain class of contact manifolds which admit…

Symplectic Geometry · Mathematics 2014-10-16 Jungsoo Kang

We define a right-invariant Riemannian metric on the group of contactomorphisms and study its Euler-Arnold equation. If the metric is associated to the contact form, the Euler-Arnold equation reduces to $m_t + u(m) + (n+2) mE(f) = 0$, in…

Analysis of PDEs · Mathematics 2014-09-09 David G. Ebin , Stephen C. Preston