Partial Cohomologically Complete Intersections via Hodge Theory

Fuente: arXiv
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Auteurs principaux: Chen, Qianyu, Dirks, Bradley, Olano, Sebastian
Format: Preprint
Publié: 2025
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author Chen, Qianyu
Dirks, Bradley
Olano, Sebastian
author_facet Chen, Qianyu
Dirks, Bradley
Olano, Sebastian
contents Using Saito's theory of mixed Hodge modules, we study a generalization of Hellus-Schenzel's "cohomologically complete intersection" property. This property is equivalent to perversity of the shifted constant sheaf. We relate the generalized version to the Hodge filtration on local cohomology, depth of Du Bois complexes, Hodge-Lyubeznik numbers and prove a striking inequality on the codimension of the non-perverse locus of the shifted constant sheaf. We study the case of cones over projective rational homology manifolds. We study when such varieties satisfy the weakened condition mentioned above as well as the partial Poincaré duality. To do this, we completely describe their higher local cohomology modules in terms of the Hodge theory of the corresponding projective variety. We apply this to the study of Hodge-Lyubeznik numbers and the intersection cohomology.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03042
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Partial Cohomologically Complete Intersections via Hodge Theory
Chen, Qianyu
Dirks, Bradley
Olano, Sebastian
Algebraic Geometry
Using Saito's theory of mixed Hodge modules, we study a generalization of Hellus-Schenzel's "cohomologically complete intersection" property. This property is equivalent to perversity of the shifted constant sheaf. We relate the generalized version to the Hodge filtration on local cohomology, depth of Du Bois complexes, Hodge-Lyubeznik numbers and prove a striking inequality on the codimension of the non-perverse locus of the shifted constant sheaf. We study the case of cones over projective rational homology manifolds. We study when such varieties satisfy the weakened condition mentioned above as well as the partial Poincaré duality. To do this, we completely describe their higher local cohomology modules in terms of the Hodge theory of the corresponding projective variety. We apply this to the study of Hodge-Lyubeznik numbers and the intersection cohomology.
title Partial Cohomologically Complete Intersections via Hodge Theory
topic Algebraic Geometry
url https://arxiv.org/abs/2511.03042