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Related papers: HKKN-stratifications in a non-compact framework

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We construct completely integrable systems on the dual of the Lie algebra of any compact Lie group $K$ with respect to the standard Lie-Poisson structure. These systems generalize key properties of Gelfand-Zeitlin systems: A) the pullback…

Symplectic Geometry · Mathematics 2025-04-22 Benjamin Hoffman , Jeremy Lane

Suppose $X$ is a compact symplectic manifold acted on by a compact Lie group $K$ (which may be nonabelian) in a Hamiltonian fashion, with moment map $\mu: X \to {\rm Lie}(K)^*$ and Marsden-Weinstein reduction $\xred = \mu^{-1}(0)/K$. There…

alg-geom · Mathematics 2008-02-03 L. C. Jeffrey , F. C. Kirwan

Given a compact K\"ahler manifold, Geometric Invariant Theory is applied to construct analytic GIT-quotients that are local models for a classifying space of (poly)stable holomorphic vector bundles containing the coarse moduli space of…

Complex Variables · Mathematics 2021-04-07 Nicholas Buchdahl , Georg Schumacher

We study relatively semi-stable vector bundles and their moduli on non-K\"ahler principal elliptic bundles over compact complex manifolds of arbitrary dimension. The main technical tools used are the twisted Fourier-Mukai transform and a…

Complex Variables · Mathematics 2013-10-02 Vasile Brinzanescu , Andrei D. Halanay , Günther Trautmann

We prove that the norm-square of a moment map associated to a linear action of a compact group on an affine variety satisfies a certain gradient inequality. This allows us to bound the gradient flow, even if we do not assume that the moment…

Symplectic Geometry · Mathematics 2014-10-16 Jonathan Fisher

Let $M$ be a connected compact quantizable K\"ahler manifold equipped with a Hamiltonian action of a connected compact Lie group $G$. Let $M//G=\phi^{-1}(0)/G=M_0$ be the symplectic quotient at value 0 of the moment map $\phi$. The space…

Symplectic Geometry · Mathematics 2009-11-13 Hui Li

We study the existence of three classes of Hermitian metrics on certain types of compact complex manifolds. More precisely, we consider balanced, SKT and astheno-K\"ahler metrics. We prove that the twistor spaces of compact hyperk\"ahler…

Differential Geometry · Mathematics 2018-02-08 Anna Fino , Gueo Grantcharov , Luigi Vezzoni

Let G be a complex reductive Lie group acting on a compact K\"ahler manifold X and assume that the action of a maximal compact subgroup K of G is Hamiltonian. For each extreme point of the convex hull of the momentum map image, there is an…

Complex Variables · Mathematics 2025-05-13 Peter Heinzner , Christian Zöller

The aim of these notes is to acquaint the reader with important objects in complex algebraic geometry: K3 surfaces and their higher-dimensional analogs, hyperk\"ahler manifolds. These manifolds are interesting from several points of view:…

Algebraic Geometry · Mathematics 2020-11-18 Olivier Debarre

Let G be a semisimple linear algebraic group defined over rational numbers, K be a maximal compact subgroup of its real points and {\Gamma} be an arithmetic lattice. One can associate a probability measure {\mu}(H) on {\Gamma}\G for each…

Dynamical Systems · Mathematics 2021-01-15 Runlin Zhang

On a class of compact Hermitian manifolds including compact K\"{a}hler manifolds, we prove that the the relative non-pluripolar product is always well-defined. We also prove the monotonicity of the relative non-pluripolar product in terms…

Differential Geometry · Mathematics 2025-06-02 Zhenghao Li , Shuang Su

I review some of my recent work on non-lorentzian geometry. I review the classification of kinematical Lie algebras and their associated Klein geometries. I then describe the Cartan geometries modelled on them and their characterisation in…

Differential Geometry · Mathematics 2022-04-29 José Figueroa-O'Farrill

A locally conformally K\"ahler (LCK) manifold is a complex manifold covered by a K\"ahler manifold, with the covering group acting by homotheties. We show that if such a compact manifold X admits a holomorphic submersion with positive…

Differential Geometry · Mathematics 2020-07-30 Liviu Ornea , Maurizio Parton , Victor Vuletescu

We formulate and prove an index theorem for loop spaces of compact manifolds in the framework of $KK$-theory. It is a strong candidate for the noncommutative geometrical definition (or the analytic counterpart) of the Witten genus. In order…

K-Theory and Homology · Mathematics 2022-08-26 Doman Takata

Let $S$ be a Riemann surface obtained by deleting a finite number of points, called cusps, from a compact Riemann surface. Let $\rho: \pi_1(S)\to Sl(n, \mathbb{C})$ be a semisimple linear representation of $\pi_1(S)$ which is unipotent near…

Algebraic Geometry · Mathematics 2007-05-23 Juergen Jost , Yi-Hu Yang , Kang Zuo

We study smooth foliations of arbitrary codimension on homogeneous compact K\"ahler manifolds. We prove that smooth foliations on rational compact homogeneous manifolds are locally trivial fibrations and classify the smooth foliations with…

Algebraic Geometry · Mathematics 2015-01-20 Federico Lo Bianco , Jorge Vitorio Pereira

We consider learning in decentralized heterogeneous networks: agents seek to minimize a convex functional that aggregates data across the network, while only having access to their local data streams. We focus on the case where agents seek…

Optimization and Control · Mathematics 2021-06-02 Hrusikesha Pradhan , Amrit Singh Bedi , Alec Koppel , Ketan Rajawat

In this paper, we study the analytic continuation to complex time of the Hamiltonian flow of certain $G\times T$-invariant functions on the cotangent bundle of a compact connected Lie group $G$ with maximal torus $T$. Namely, we will take…

Differential Geometry · Mathematics 2019-09-10 José M. Mourão , João P. Nunes , Miguel B. Pereira

In this long note, we investigate various purely topological aspects of non-Hausdorff manifolds (NH-manifolds for short). Our emphasis is on manifolds which exhibit homogeneity or weakenings thereof, in particular being everywhere…

General Topology · Mathematics 2026-03-26 Mathieu Baillif

Let K be a compact Lie group and fix an invariant inner product on its Lie algebra. Given a Hamiltonian action of K on a compact symplectic manifold X, the normsquare of the moment map defines a Morse stratification of X by locally closed…

Algebraic Geometry · Mathematics 2018-02-27 Frances Kirwan