Localizing invariants of constructible sheaves

Qingyuan Bai; Peter J. Haine

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arXiv · 2512.12810

Localizing invariants of constructible sheaves

Qingyuan Bai·Peter J. Haine

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Abstract

Given an open-closed decomposition of the stratifying poset, we construct a new semi-orthogonal decomposition of the $\infty$-category of constructible sheaves on a stratified space admitting an exit-path $\infty$-category. From this we obtain a direct sum decomposition of the localizing invariants of the $\infty$-category of constructible sheaves. Since the $\ast$-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 $\ast$-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.

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Qingyuan Bai, Peter J. Haine. 2025-12-14. Localizing invariants of constructible sheaves. https://arxiv.org/abs/2512.12810

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