English
Related papers

Related papers: On Sha's secondary Chern-Euler class

200 papers

For two complex vector bundles admitting a homomorphism with isolated singularities between them, we establish a Poincar\'e-Hopf type formula for the difference of the Chern character numbers of these two vector bundles. As a consequence,…

Geometric Topology · Mathematics 2010-06-14 Huitao Feng , Weiping Li , Weiping Zhang

Let $M$ be a non-compact connected manifold with a cocompact and properly discontinuous action of a discrete group $G$. We establish a Poincar\'{e}-Hopf theorem for a bounded vector field on $M$ satisfying a mild condition on zeros. As an…

Geometric Topology · Mathematics 2024-12-18 Tsuyoshi Kato , Daisuke Kishimoto , Mitsunobu Tsutaya

In this article, we study the topological complexity of manifolds with a lower scalar curvature bound. We introduce a small scale index theorem to establish an upper bound for Gromov's simplicial norm of the Poincar\'e dual of the A-hat…

Differential Geometry · Mathematics 2025-11-05 Qiaochu Ma , Guoliang Yu

In this paper we show how to translate into tensorial language the Chern-Weil theorem for the Lorentz symmetry, which equates the difference of the Euler densities of two manifolds to the exterior derivative of a transgression form. For…

General Relativity and Quantum Cosmology · Physics 2018-08-29 Nathalie Deruelle , Nelson Merino , Rodrigo Olea

Tsuboi proved that the Calabi invariant of the closed disk transgresses to the Euler class of foliated circle bundles and suggested looking for its higher-dimensional analog. In this paper, we construct a cohomology class of the group of…

Geometric Topology · Mathematics 2024-06-04 Shuhei Maruyama

We generalize Roe's Index Theorem for operators of Dirac type on open manifolds to elliptic pseudodifferential operators. To this end we introduce a class of pseudodifferential operators on manifolds of bounded geometry which is more…

Differential Geometry · Mathematics 2014-10-30 Alexander Engel

We consider closed manifolds that admit a metric locally isometric to a product of symmetric planes. For such manifolds, we prove that the Euler characteristic is an obstruction to the existence of flat structures, confirming an old…

Geometric Topology · Mathematics 2009-05-23 Michelle Bucher , Tsachik Gelander

The purpose of this short note is to prove a formula for the Chern-Mather classes of a toric variety in terms of its orbits and the local Euler obstructions at general points of each orbit (Theorem 2). We use the general definition of the…

Algebraic Geometry · Mathematics 2016-04-12 Ragni Piene

In this short note we outline a simple probabilistic proof of the Gauss-Bonnet formula for compact Riemannian manifolds with boundary, which adapts to this setting an argument due to Hsu \cite{Hs1,Hs2} in the closed case. The new technical…

Differential Geometry · Mathematics 2017-09-13 Levi Lopes de Lima

We discuss secondary (and higher) characteristic classes for algebraic vector bundles with trivial top Chern class. We show that if X is a smooth affine scheme of dimension d over a field k of finite 2-cohomological dimension (with char(k)…

Algebraic Geometry · Mathematics 2015-04-13 Aravind Asok , Jean Fasel

In this note, we extend the theory of Chern-Cheeger-Simons to construct canonical invariants for a one-parameter family of flat connections on a smooth manifold. These invariants lie in degrees $(2p-2)$-cohomology with $\C/\Z$-cohomology,…

Differential Geometry · Mathematics 2013-10-02 Jaya NN Iyer

We define the equivariant Chern-Schwartz-MacPherson class of a possibly singular algebraic variety with a group action over the complex number field (or a field of characteristic 0). In fact, we construct a natural transformation from the…

Algebraic Geometry · Mathematics 2009-11-10 Toru Ohmoto

We prove two geometric index theorems for a family of first-order elliptic operators over a manifold with boundary by computing eta form representatives for the Chern character classes of the index bundle. The eta forms occur as relative…

Differential Geometry · Mathematics 2007-05-23 S. Scott

In this note we prove a conjecture of Kashiwara, which states that the Euler class of a coherent analytic sheaf F on a complex manifold X is the product of the Chern character of F with the Todd class of X. As a corollary, we obtain a…

Algebraic Geometry · Mathematics 2017-10-10 Julien Grivaux

We define transgressions of arbitrary order, with respect to families of unit-vector fields indexed by a polytope, for the Pfaffian of metric connections for semi-Riemannian metrics on vector bundles. We apply this formula to compute the…

Differential Geometry · Mathematics 2021-11-29 Sergiu Moroianu

This paper presents a new reformulated theorem for fields embedded on a sphere or a disk. We focus in particular on the associated sphere of a disk when closing its only one boundary. We call this the disk-sphere duality theorem for the…

Mathematical Physics · Physics 2018-12-05 Tristan Maquart

This work is a short, self-contained introduction to subriemannian geometry with special emphasis on Chow's Theorem. As an application, a regularity result for the Poincar\'e Lemma is presented. At the beginning, the definitions of a…

Differential Geometry · Mathematics 2012-11-16 Philipp Harms

For two complex vector bundles admitting a homomorphism between them, a Poincar\'e-Hopf formula for the difference of the Chern character numbers of these two vector bundles with isolated singularities is established by Huitao Feng, Weiping…

Differential Geometry · Mathematics 2022-10-18 Xu Chen

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

We show that assuming lower bounds on the Ricci curvature and the injectivity radius the absolute value of certain characteristic numbers of a Riemannian manifold, including all Pontryagin and Chern numbers, is bounded proportionally to the…

Differential Geometry · Mathematics 2021-05-18 Daniel Luckhardt