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Journal of Algebraic Geometry

Journal of Algebraic Geometry

Online ISSN 1534-7486; Print ISSN 1056-3911

   
 
 

 

All 81 crepant resolutions of a finite quotient singularity are hyperpolygon spaces


Authors: Gwyn Bellamy, Alastair Craw, Steven Rayan, Travis Schedler and Hartmut Weiss
Journal: J. Algebraic Geom.
DOI: https://doi.org/10.1090/jag/827
Published electronically: April 1, 2024
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Abstract | References | Additional Information

Abstract: We demonstrate that the linear quotient singularity for the exceptional subgroup $G$ in $\mathrm {Sp}(4,\mathbb {C})$ of order 32 is isomorphic to an affine quiver variety for a 5-pointed star-shaped quiver. This allows us to construct uniformly all 81 projective crepant resolutions of $\mathbb {C}^4/G$ as hyperpolygon spaces by variation of GIT quotient, and we describe both the movable cone and the Namikawa Weyl group action via an explicit hyperplane arrangement. More generally, for the $n$-pointed star shaped quiver, we describe completely the birational geometry for the corresponding hyperpolygon spaces in dimension $2n-6$; for example, we show that there are 1684 projective crepant resolutions when $n=6$. We also prove that the resulting affine cones are not quotient singularities for $n \geq 6$.


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Gwyn Bellamy
Affiliation: School of Mathematics and Statistics, University of Glasgow, University Place, Glasgow G12 8QQ, United Kingdom
MR Author ID: 857289
ORCID: 0000-0002-7045-4177
Email: gwyn.bellamy@glasgow.ac.uk

Alastair Craw
Affiliation: Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
MR Author ID: 683635
Email: a.craw@bath.ac.uk

Steven Rayan
Affiliation: Department of Mathematics and Statistics and Centre for Quantum Topology and Its Applications (quanTA), University of Saskatchewan, McLean Hall, 106 Wiggins Road, Saskatoon SK, S7N 5E6, Canada
MR Author ID: 940734
ORCID: 0000-0003-0273-1598
Email: rayan@math.usask.ca

Travis Schedler
Affiliation: Imperial College London, Huxley Building, South Kensington Campus, London SW7 2AZ, United Kingdom
MR Author ID: 655427
ORCID: 0000-0001-7301-2932
Email: t.schedler@imperial.ac.uk

Hartmut Weiss
Affiliation: Mathematisches Seminar, Christian-Albrechts-Universität Kiel, Heinrich-Hecht-Platz 6, Kiel D-24118, Germany
MR Author ID: 777371
ORCID: 0000-0003-1928-2725
Email: weiss@math.uni-kiel.de

Received by editor(s): June 9, 2022
Received by editor(s) in revised form: September 5, 2023
Published electronically: April 1, 2024
Additional Notes: The first and second authors were partially supported by Research Project Grant RPG-2021-149 from the Leverhulme Trust. The third author was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant. The fifth author was supported by the Deutsche Forschungsgemeinschaft (DFG) within SPP 2026 “Geometry at infinity”.
Article copyright: © Copyright 2024 University Press, Inc.