25 citations · 26 across the 4 of their papers we have counts for
4 papers
A Hopf index for isotropic sections of orthogonal bundles
Martijn Kool, Jeongseok Oh, Jørgen Vold Rennemo +1
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 fo…
Refined sheaf counting on local K3 surfaces
Richard P. Thomas
We compute all refined sheaf counting invariants -- Vafa-Witten, reduced DT, stable pairs and Gopakumar-Vafa -- for all classes on local surfaces. Along the way we develop ran…
Quantum Lefschetz without curves
Jeongseok Oh, Richard P. Thomas
Given one quasi-smooth derived space cut out of another by a section of a 2-term complex of bundles, we give two formulae for its virtual cycle. They are modelled on the the -fi…
Degeneracy loci, virtual cycles and nested Hilbert schemes I
Amin Gholampour, Richard P. Thomas
Given a map of vector bundles on a smooth variety, consider the deepest degeneracy locus where its rank is smallest. We show it carries a natural perfect obstruction theory whose v…