Localizing invariants of constructible sheaves
Abstract
Given an open-closed decomposition of the stratifying poset, we construct a new semi-orthogonal decomposition of the -category of constructible sheaves on a stratified space admitting an exit-path -category. From this we obtain a direct sum decomposition of the localizing invariants of the -category of constructible sheaves. Since the -pullback to the open stratum in the usual (recollement) semi-orthogonal decomposition is not strongly left adjoint, this splitting does not follow from pure sheaf theory considerations. Instead, the splitting crucially relies on the exodromy equivalence: it implies that on the level of constructible sheaves, the -pullback to a closed stratum and the -pushforward from an open stratum admit left adjoints. These new functors provide an additional semi-orthogonal decomposition (with the roles of open and closed reversed) in which the relevant functors are strongly left adjoint.
Cite
@article{arxiv.2512.12810,
title = {Localizing invariants of constructible sheaves},
author = {Qingyuan Bai and Peter J. Haine},
journal= {arXiv preprint arXiv:2512.12810},
year = {2026}
}
Comments
Comments very welcome. v2. 20 pages. Corrected a typo in a formula in Proposition 2.6