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Related papers: An index theorem on anti-self-dual orbifolds

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We study infinitesimal deformations of Lie algebroid pairs in the category of smooth manifolds enriched with a local Artinian algebra. Given a Lie algebroid pair $(L,A)$, i.e. a Lie algebroid $L$ together with a Lie subalgebroid $A$, we…

Differential Geometry · Mathematics 2025-12-04 Dadi Ni , Zhuo Chen , Chuangqiang Hu , Maosong Xiang

We give new and rather general gluing theorems for anti-self-dual (ASD) conformal structures, following the method suggested by Floer. The main result is a gluing theorem for pairs of conformally ASD manifolds `joined' across a common piece…

Differential Geometry · Mathematics 2007-05-23 A. G. Kovalev , M. A. Singer

We obtain a compactness result for various classes of Riemannian metrics in dimension four; in particular our method applies to anti-self-dual metrics, Kahler metrics with constant scalar curvature, and metrics with harmonic curvature. With…

Differential Geometry · Mathematics 2009-08-26 Jeff Viaclovsky , Gang Tian

For moduli space of stable parabolic bundles on a compact Riemann surface, we derive an explicit formula for the curvature of its canonical line bundle with respect to Quillen's metric and interpret it as a local index theorem for the…

Algebraic Geometry · Mathematics 2015-01-12 Leon A. Takhtajan , Peter G. Zograf

A new construction is presented of scalar-flat Kaehler metrics on non-minimal ruled surfaces. The method is based on the resolution of singularities of orbifold ruled surfaces which are closely related to rank-2 parabolically stable…

Differential Geometry · Mathematics 2007-05-23 Yann Rollin , Michael A. Singer

In this paper we announce a gluing theorem for conformal structures with anti-self-dual (ASD) Weyl tensor that applies in geometrical situations that are more general than those considered by previous authors. By adapting a method proposed…

Differential Geometry · Mathematics 2007-05-23 A. G. Kovalev , M. A. Singer

We classify compact self-dual almost-K\"ahler four manifolds of positive type and zero type. In particular, using LeBrun's result, we show that any self-dual almost-K\"ahler metric on a manifold which is diffeomorphic to $\mathbb{CP}_{2}$…

Differential Geometry · Mathematics 2023-11-30 Inyoung Kim

We construct the normal forms of null-K\"ahler metrics: pseudo-Riemannian metrics admitting a compatible parallel nilpotent endomorphism of the tangent bundle. Such metrics are examples of non-Riemannian holonomy reduction, and (in the…

Differential Geometry · Mathematics 2021-12-22 Maciej Dunajski

We prove that a closed oriented Einstein four-manifold is either anti-self-dual or (after passing to a double Riemann cover if necessary) K\"ahler-Einstein, provided that $\lambda_2 \geq -\frac{S}{12}$, where $\lambda_2$ is the middle…

Differential Geometry · Mathematics 2022-06-13 Xiaolong Li , Yongjia Zhang

We show that, under Dubrovin's notion of ''almost'' duality, the Frobenius manifold structure on the orbit spaces of the extended affine Weyl groups of type $\mathrm{ADE}$ is dual, for suitable choices of weight markings, to the equivariant…

Algebraic Geometry · Mathematics 2025-12-01 Andrea Brini , Jingxiang Ma , Ian A. B. Strachan

We prove the existence of perturbations for the PU(2) monopole equations, yielding transversality on the complement of the anti-self-dual or reducible solutions, and the existence of an Uhlenbeck compactification for the moduli space of…

dg-ga · Mathematics 2016-08-31 Paul M. N. Feehan , Thomas G. Leness

In this paper we show an abundance of complete K\"ahler metrics with negative holomorphic bisectional curvature on total spaces of certain vector bundles. Assume that such total spaces are endowed with a wider class of nonpositively curved…

Differential Geometry · Mathematics 2025-11-18 Hanyu Wu , Bo Yang

We endow the group of automorphisms of an exact Courant algebroid over a compact manifold with an infinite dimensional Lie group structure modelled on the inverse limit of Hilbert spaces (ILH). We prove a slice theorem for the action of…

Differential Geometry · Mathematics 2020-04-10 Roberto Rubio , Carl Tipler

We prove a general relative higher index theorem for complete manifolds with positive scalar curvature towards infinity. We apply this theorem to study Riemannian metrics of positive scalar curvature on manifolds. For every two metrics of…

K-Theory and Homology · Mathematics 2012-08-27 Zhizhang Xie , Guoliang Yu

In this work, we determine explicitly the anomaly line bundle of the abelian self-dual field theory over the space of metrics modulo diffeomorphisms, including its torsion part. Inspired by the work of Belov and Moore, we propose a…

High Energy Physics - Theory · Physics 2014-01-09 Samuel Monnier

This paper gives an elementary introduction to noncommutative deformations of modules. The main results of this deformation theory are due to Laudal. Let k be an algebraically closed (commutative) field, let A be an associative k-algebra,…

Algebraic Geometry · Mathematics 2007-05-23 Eivind Eriksen

We prove a geometric criterion on a $\SL$-invariant ergodic probability measure on the moduli space of holomorphic abelian differentials on Riemann surfaces for the non-uniform hyperbolicity of the Kontsevich--Zorich cocycle on the real…

Dynamical Systems · Mathematics 2011-03-25 Giovanni Forni

This article gives an exposition of the deformation theory for pairs $(X, E)$, where $X$ is a compact complex manifold and $E$ is a holomorphic vector bundle over $X$, adapting an analytic viewpoint \`{a} la Kodaira-Spencer. By introducing…

Differential Geometry · Mathematics 2016-02-16 Kwokwai Chan , Yat-Hin Suen

We say that a Lie (super)algebra is ''symmetric'' if with every root (with respect to the maximal torus) it has the opposite root of the same multiplicity. Over algebraically closed fields of positive characteristics (up to 7 or 11, enough…

Representation Theory · Mathematics 2024-09-17 Sofiane Bouarroudj , Pavel Grozman , Dimitry Leites

There are many known examples of scalar-flat K\"ahler ALE surfaces, all of which have group at infinity either cyclic or contained in ${\rm{SU}}(2)$. The main result in this paper shows that for any non-cyclic finite subgroup $\Gamma…

Differential Geometry · Mathematics 2016-05-23 Michael T. Lock , Jeff A. Viaclovsky