Microlocal homology

Fuente: arXiv
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Main Author: Schefers, Kendric
Format: Preprint
Published: 2022
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author Schefers, Kendric
author_facet Schefers, Kendric
contents Let $Z$ be an l.c.i. scheme over $\mathbb{C}$. In this paper, we introduce a Kashiwara--Schapira-style functor of derived microlocalization, which we use to define a perverse sheaf $μ_{Z}$ on the $-1$-shifted cotangent bundle, $T^*[-1]Z$. The sheaf $μ_{Z}$ is designed to be a refinement of the microlocal homology of $Z$: a family of invariants introduced by Nadler that interpolates between the singular cohomology and Borel--Moore homology of $Z$. Our main result is an equivalence between $μ_{Z}$ and the DT sheaf $φ_{T^*[-1]Z}$ on $T^*[-1]Z$. This provides an alternative construction for the DT sheaf in the case of a shifted cotangent bundle. The main step of our argument, which may be of independent interest, is a local computation -- closely related to one obtained recently by Kinjo using different methods -- providing a description of the classical microlocalization functor in terms of vanishing cycles.
format Preprint
id arxiv_https___arxiv_org_abs_2205_12436
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Microlocal homology
Schefers, Kendric
Algebraic Geometry
Representation Theory
Let $Z$ be an l.c.i. scheme over $\mathbb{C}$. In this paper, we introduce a Kashiwara--Schapira-style functor of derived microlocalization, which we use to define a perverse sheaf $μ_{Z}$ on the $-1$-shifted cotangent bundle, $T^*[-1]Z$. The sheaf $μ_{Z}$ is designed to be a refinement of the microlocal homology of $Z$: a family of invariants introduced by Nadler that interpolates between the singular cohomology and Borel--Moore homology of $Z$. Our main result is an equivalence between $μ_{Z}$ and the DT sheaf $φ_{T^*[-1]Z}$ on $T^*[-1]Z$. This provides an alternative construction for the DT sheaf in the case of a shifted cotangent bundle. The main step of our argument, which may be of independent interest, is a local computation -- closely related to one obtained recently by Kinjo using different methods -- providing a description of the classical microlocalization functor in terms of vanishing cycles.
title Microlocal homology
topic Algebraic Geometry
Representation Theory
url https://arxiv.org/abs/2205.12436