English

Hodge modules and cobordism classes

Algebraic Geometry 2022-04-20 v5

Abstract

We show that the cobordism class of a polarization of Hodge module defines a natural transformation from the Grothendieck group of Hodge modules to the cobordism group of self-dual bounded complexes with real coefficients and constructible cohomology sheaves in a compatible way with pushforward by proper morphisms. This implies a new proof of the well-definedness of the natural transformation from the Grothendieck group of varieties over a given variety to the above cobordism group (with real coefficients). As a corollary, we get a slight extension of a conjecture of Brasselet, Sch\"urmann and Yokura, showing that in the Q\mathbb Q-homologically isolated singularity case, the homology LL-class which is the specialization of the Hirzebruch class coincides with the intersection complex LL-class defined by Goresky, MacPherson, and others if and only if the sum of the reduced modified Euler-Hodge signatures of the stalks of the shifted intersection complex vanishes. Here Hodge signature uses a polarization of Hodge structure, and it does not seem easy to define it by a purely topological method.

Keywords

Cite

@article{arxiv.2103.04836,
  title  = {Hodge modules and cobordism classes},
  author = {Javier Fernández de Bobadilla and Irma Pallarés and Morihiko Saito},
  journal= {arXiv preprint arXiv:2103.04836},
  year   = {2022}
}

Comments

21 pages

R2 v1 2026-06-23T23:52:49.351Z