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Related papers: A generalized Poincar\'e-Hopf index theorem

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A Poincar\'{e}-Hopf theorem in the spirit of Pugh is proven for compact orbifolds with boundary. The theorem relates the index sum of a smooth vector field in generic contact with the boundary orbifold to the Euler-Satake characteristic of…

Differential Geometry · Mathematics 2009-04-06 Elliot Paquette , Christopher Seaton

The Poincar\'e-Hopf theorem for line fields, as described in a paper of Crowley and Grant, is interpreted as a special case of a Poincar\'e-Hopf theorem for $n$-valued sections of a vector bundle over a closed manifold of the same…

Algebraic Topology · Mathematics 2025-02-28 M. C. Crabb

The Poincar\'e-Hopf Theorem is a conservation law for real-analytic vector fields, which are tangential to a closed surface (such as a torus or a sphere). The theorem also governs real-analytic vector fields, which are tangential to…

Analysis of PDEs · Mathematics 2022-10-04 Aaron Pim

A generalization of the Poincar\'{e}-Hopf index theorem applicable to hybrid dynamical systems is obtained. For the hybrid systems considered, guard sets are not assumed to be smooth; distinct "modes" are not assumed to have constant…

Dynamical Systems · Mathematics 2024-10-28 Matthew D. Kvalheim

The goal of this work is to generalize the Gauss-Bonnet and Poincar\'{e}-Hopf Theorems to the case of orbifolds with boundary. We present two such generalizations, the first in the spirit of Satake. In this case, the local data (i.e.…

Differential Geometry · Mathematics 2008-06-09 Christopher Seaton

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

The Poincar\'e-Hopf Theorem relates the Euler characteristic of a 2-dimensional compact manifold to the local behavior of smooth vector fields defined on it. However, despite the importance of Filippov vector fields, concerning both their…

Dynamical Systems · Mathematics 2024-09-18 Joyce A. Casimiro , Ricardo M. Martins , Douglas D. Novaes

Indices of singular points of a vector field or of a 1-form on a smooth manifold are closely related with the Euler characteristic through the classical Poincar\'e--Hopf theorem. Generalized Euler characteristics (additive topological…

Geometric Topology · Mathematics 2019-03-19 S. M. Gusein-Zade

We compute (algebraically) the Euler characteristic of a complex of sheaves with constructible cohomology. A stratified Poincar\'e-Hopf formula is then a consequence of the smooth Poincar\'e-Hopf theorem and of additivity of the…

Algebraic Topology · Mathematics 2009-05-29 Stéphane Simon

A Poincar\'e-Hopf Theorem for line fields with point singularities on orientable surfaces can be found Hopf's 1956 Lecture Notes on Differential Geometry. In 1955 Markus presented such a theorem in all dimensions, but Markus' statement only…

Algebraic Topology · Mathematics 2017-04-26 Diarmuid Crowley , Mark Grant

Let $X$ be a projective algebraic $d$-variety endowed with isolated determinantal singularities, and let $\omega$ be a $1$-form on $X$ exhibiting a finite number of singularities (in the stratified sense). Under some technical conditions,…

Geometric Topology · Mathematics 2026-05-08 N. G. Grulha , M. S. Pereira , H. Santana

Let $X \subset\mathbb{P}^r$ be a projective $d$-variety with isolated determinantal singularities and $\omega$ be a $1$-form on $X$ with a finite number of singularities (in the stratified sense). Under some technical conditions on $r$ we…

Geometric Topology · Mathematics 2026-04-17 N. G. Grulha , M. S. Pereira , H. Santana

The Poincare-Hopf Theorem is one of the most used in other areas of science. There are applications of the Poincare-Hopf Theorem in physics, chemistry, biology and even in economics, psychology, etc ... The Poincare-Hopf Theorem connects an…

History and Overview · Mathematics 2023-05-16 Jean-Paul Brasselet , Nguyen Thi Bich Thuy

We formulate and prove an analog of the Hopf Index Theorem for Riemannian foliations. We compute the basic Euler characteristic of a closed Riemannian manifold as a sum of indices of a non-degenerate basic vector field at critical leaf…

Differential Geometry · Mathematics 2021-01-28 Victor Belfi , Efton Park , Ken Richardson

For a compact differentiable surface with boundary embedded in $\Bbb R^3$, we give simple proofs of the Gauss-Bonnet theorem, Poincar\'{e}-Hopf theorem, and several other integral formulas. We complete all of the proofs without using…

Differential Geometry · Mathematics 2015-09-17 Daniel Mayost

In this paper, we employ the framework of localization algebras to compute the equivariant K-homology class of the Euler characteristic operator, a central object in studying equivariant index theory on manifolds. This approach provides a…

Algebraic Topology · Mathematics 2024-10-22 Hongzhi Liu , Hang Wang , Zijing Wang , Shaocong Xiang

We generalize Roe's index theorem for graded generalized Dirac operators on amenable manifolds to multigraded elliptic uniform pseudodifferential operators. The generalization will follow from a local index theorem that is valid on any…

Differential Geometry · Mathematics 2018-06-07 Alexander Engel

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

We extend the Poincare'-Lyapounov-Nekhoroshev theorem from torus actions and invariant tori to general (non-abelian) involutory systems of vector fields and general invariant manifolds.

Mathematical Physics · Physics 2009-11-11 G. Gaeta

A vector field X on a manifold M with possibly nonempty boundary is inward if it generates a unique local semiflow $\Phi^X$. A compact relatively open set K in the zero set of X is a block. The Poincar\'e-Hopf index is generalized to an…

Dynamical Systems · Mathematics 2012-04-30 Morris W. Hirsch
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