A Hopf index for isotropic sections of orthogonal bundles

International Mathematics Research Notices 2026 Open access

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Authors: Martijn Kool, Jeongseok Oh, Jørgen Vold Rennemo, Richard P. Thomas
DOI: 10.1093/imrn/rnag077
Cited by: 0

Abstract

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$^{4}$ virtual cycles.

Fields of Study & Subjects

Advanced Algebra and Geometry

Publication details

Journal / source
International Mathematics Research Notices
Volume
2026
Issue
10
Publication date
3 April 2026
Language
EN