A Hopf index for isotropic sections of orthogonal bundles
Algebraic Geometry
2025-02-28 v2 Algebraic Topology
Abstract
The Hopf index equates the multiplicity of a zero of a section of a vector bundle with a winding number. We give eight analogues for isotropic sections of bundles with quadratic form. There are applications to cosection localised virtual cycles and to DT virtual cycles.
Cite
@article{arxiv.2502.13050,
title = {A Hopf index for isotropic sections of orthogonal bundles},
author = {Martijn Kool and Jeongseok Oh and Jørgen Vold Rennemo and Richard P Thomas},
journal= {arXiv preprint arXiv:2502.13050},
year = {2025}
}
Comments
27 pages, minor updates