Perverse sheaves on Riemann surfaces as Milnor sheaves

Constructible sheaves of abelian groups on a stratified space can be equivalently described in terms of representations of the exit-path category. In this work, we provide a similar presentation of the abelian category of perverse sheaves on a stratified surface in terms of representations of the so...

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Main Authors: Tobias Dyckerhoff, Mikhail Kapranov, Yan Soibelman
Format: Article
Language:English
Published: Cambridge University Press 2023-01-01
Series:Forum of Mathematics, Sigma
Subjects:
Online Access:https://www.cambridge.org/core/product/identifier/S2050509423000841/type/journal_article
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author Tobias Dyckerhoff
Mikhail Kapranov
Yan Soibelman
author_facet Tobias Dyckerhoff
Mikhail Kapranov
Yan Soibelman
author_sort Tobias Dyckerhoff
collection DOAJ
description Constructible sheaves of abelian groups on a stratified space can be equivalently described in terms of representations of the exit-path category. In this work, we provide a similar presentation of the abelian category of perverse sheaves on a stratified surface in terms of representations of the so-called paracyclic category of the surface. The category models a hybrid exit–entrance behaviour with respect to chosen sectors of direction, placing it ‘in between’ exit and entrance path categories. In particular, this perspective yields an intrinsic definition of perverse sheaves as an abelian category without reference to derived categories and t-structures.
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spelling doaj.art-1759d0843f564faaa922b0707316e6692023-10-06T09:27:56ZengCambridge University PressForum of Mathematics, Sigma2050-50942023-01-011110.1017/fms.2023.84Perverse sheaves on Riemann surfaces as Milnor sheavesTobias Dyckerhoff0Mikhail Kapranov1Yan Soibelman2Universität Hamburg, Fachbereich Mathematik, Bundesstrasse 55, 20146 Hamburg, Germany; E-mail:Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba, 277-8583 Japan; E-mail:Dept. Math., Kansas State University, Manhattan, KS 66506 USA; E-mail:Constructible sheaves of abelian groups on a stratified space can be equivalently described in terms of representations of the exit-path category. In this work, we provide a similar presentation of the abelian category of perverse sheaves on a stratified surface in terms of representations of the so-called paracyclic category of the surface. The category models a hybrid exit–entrance behaviour with respect to chosen sectors of direction, placing it ‘in between’ exit and entrance path categories. In particular, this perspective yields an intrinsic definition of perverse sheaves as an abelian category without reference to derived categories and t-structures.https://www.cambridge.org/core/product/identifier/S2050509423000841/type/journal_article32S6014F0818N2518N60
spellingShingle Tobias Dyckerhoff
Mikhail Kapranov
Yan Soibelman
Perverse sheaves on Riemann surfaces as Milnor sheaves
Forum of Mathematics, Sigma
32S60
14F08
18N25
18N60
title Perverse sheaves on Riemann surfaces as Milnor sheaves
title_full Perverse sheaves on Riemann surfaces as Milnor sheaves
title_fullStr Perverse sheaves on Riemann surfaces as Milnor sheaves
title_full_unstemmed Perverse sheaves on Riemann surfaces as Milnor sheaves
title_short Perverse sheaves on Riemann surfaces as Milnor sheaves
title_sort perverse sheaves on riemann surfaces as milnor sheaves
topic 32S60
14F08
18N25
18N60
url https://www.cambridge.org/core/product/identifier/S2050509423000841/type/journal_article
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