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Related papers: Homological indices of collections of 1-forms

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We define an index of a collection of 1-forms on a complex isolated complete intersection singularity corresponding to a Chern number and, in the case when the 1-forms are complex analytic, express it as the dimension of a certain algebra.

Algebraic Geometry · Mathematics 2007-05-23 Wolfgang Ebeling , Sabir M. Gusein-Zade

For a G-invariant holomorphic 1-form with an isolated singular point on a germ of a complex-analytic G-variety with an isolated singular point (G is a finite group) one has notions of the equivariant homological index and of the (reduced)…

Algebraic Geometry · Mathematics 2017-01-10 Sabir M. Gusein-Zade , Firuza I. Mamedova

We introduce a notion of a homological index of a holomorphic 1-form on a germ of a complex analytic variety with an isolated singularity, inspired by X. G\'omez-Mont and G.-M. Greuel. For isolated complete intersection singularities it…

Algebraic Geometry · Mathematics 2007-05-23 W. Ebeling , S. M. Gusein-Zade , J. Seade

We introduce a certain index of a collection of germs of 1-forms on a germ of a singular variety which is a generalization of the local Euler obstruction corresponding to Chern numbers different from the top one.

Algebraic Geometry · Mathematics 2007-05-23 Wolfgang Ebeling , Sabir M. Gusein-Zade

There are some generalizations of the classical Eisenbud-Levine-Khimshashvili formula for the index of a singular point of an analytic vector field on $R^n$ for vector fields on singular varieties. We offer an alternative approach based on…

Algebraic Geometry · Mathematics 2016-09-07 Wolfgang Ebeling , Sabir M. Gusein-Zade

If two G-manifolds are G-cobordant then characteristic numbers corresponding to the fixed point sets (submanifolds) of subgroups of G and to normal bundles to these sets coincide. We construct two analogues of these characteristic numbers…

Algebraic Geometry · Mathematics 2014-06-18 Wolfgang Ebeling , Sabir M. Gusein-Zade

We consider manifolds with isolated singularities, i.e., topological spaces which are manifolds (say, $C^\infty$--) outside discrete subsets (sets of singular points). For (germs of) manifolds with, so called, cone--like singularities, a…

alg-geom · Mathematics 2007-05-23 Wolfgang Ebeling , Sabir M. Gusein-Zade

Indices of vector fields on (complex analytic) singular varieties have been considered by various authors from several different viewpoints. All these indices coincide with the classical local index of Poincar\'e-Hopf when the ambient…

Algebraic Geometry · Mathematics 2007-05-23 Jose Seade

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 consider 1-forms on, so called, essentially isolated determinantal singularities (a natural generalization of isolated ones), show how to define analogues of the Poincar\'e--Hopf index for them, and describe relations between these…

Algebraic Geometry · Mathematics 2008-06-03 W. Ebeling , S. M. Gusein-Zade

We discuss different generalizations of the classical notion of the index of a singular point of a vector field to the case of vector fields or 1-forms on singular varieties, describe relations between them and formulae for their…

Algebraic Geometry · Mathematics 2007-05-23 Wolfgang Ebeling , Sabir M. Gusein-Zade

Let (V,0) be a germ of a complete intersection variety in \CC^{n+k}, n>0, having an isolated singularity at 0 and X be the germ of a holomorphic vector field on \CC^{n+k} tangent to V and having on V an isolated zero at 0. We show that in…

Algebraic Geometry · Mathematics 2009-07-10 H. -Chr. Graf von Bothmer , W. Ebeling , X. Gomez-Mont

We define local residues of holomorphic 1-forms on an isolated surface singularity that have isolated zeros and prove that a certain residue equals the index of the 1-forms.

Algebraic Geometry · Mathematics 2007-05-23 Oliver Klehn

We discuss the notions of indices of vector fields and 1-forms and their generalizations to singular varieties and varieties with actions of finite groups, as well as indices of collections of vector fields and 1-forms.

Algebraic Geometry · Mathematics 2021-07-06 Wolfgang Ebeling , Sabir M. Gusein-Zade

A survey of some results and open questions related to the following algebraic invariants of compact complex manifolds, that can be obtained from differential forms: cohomology groups, Chern classes, rational homotopy groups, and higher…

Algebraic Topology · Mathematics 2025-03-11 Jonas Stelzig

In this paper we construct a Universal chain complex, counting zeros of closed 1-forms on a manifold. The Universal complex is a refinement of the well known Novikov complex; it relates the homotopy type of the manifold, after a suitable…

Differential Geometry · Mathematics 2007-05-23 M. Farber

This article is about 1-forms on complex analytic varieties and it is particularly relevant when the variety has non-isolated singularities. We first show how the radial extension technique of M.-H. Schwartz can be adapted to 1-forms,…

Algebraic Geometry · Mathematics 2007-05-23 J. -P. Brasselet , J. Seade , T. Suwa

The radial index of a 1-form on a singular set is a generalization of the classical Poincar\'e-Hopf index. We consider different classes of closed semi-analytic sets in R^n that contain 0 in their singular locus and we relate the radial…

Algebraic Geometry · Mathematics 2017-05-24 Nicolas Dutertre

For two complex vector bundles admitting a homomorphism, whose singularity locates in the disjoint union of some odd--dimensional spheres, we give a formula to compute the relative Chern characteristic number of these two complex vector…

Differential Geometry · Mathematics 2017-10-26 Dexie Lin

We introduce a cohomology, called extendable cohomology, for abstract complex singular varieties based on suitable differential forms. Beside a study of the general properties of such a cohomology, we show that, given a complex vector…

Complex Variables · Mathematics 2008-12-04 Carlo Perrone
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