NCCRs of cones over del Pezzo surfaces

Fuente: arXiv
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Main Authors: Nordskova, Anya, Bergh, Michel Van den
Format: Preprint
Published: 2026
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author Nordskova, Anya
Bergh, Michel Van den
author_facet Nordskova, Anya
Bergh, Michel Van den
contents Non-commutative crepant resolutions (NCCRs) are non-commutative versions of classical crepant resolutions in algebraic geometry. For 3-dimensional terminal Gorenstein singularities Iyama and Wemyss proved that all NCCRs are connected by mutations, which may be viewed as a non-commutative analogue of Kawamata's result that all crepant resolutions are connected by flops. In this paper we prove the corresponding result for a class of canonical Gorenstein singularities which are not terminal, namely anticanonical cones over del Pezzo surfaces. More precisely, we first obtain a classification of NCCRs of anticanonical del Pezzo cones, showing that every NCCR arises from a geometric helix on the corresponding del Pezzo surface. We then prove that all such geometric helices are connected to each other by mutations, up to simple operations which include tensoring by line bundles and shifts. A crucial ingredient in our proofs is the polygons that can be associated to exceptional collections on del Pezzo surfaces following the works of Hille and Perling. We obtain some interesting observations about these polygons which may be of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2604_11319
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle NCCRs of cones over del Pezzo surfaces
Nordskova, Anya
Bergh, Michel Van den
Algebraic Geometry
16E35, 14F08, 14A22, 14E30
Non-commutative crepant resolutions (NCCRs) are non-commutative versions of classical crepant resolutions in algebraic geometry. For 3-dimensional terminal Gorenstein singularities Iyama and Wemyss proved that all NCCRs are connected by mutations, which may be viewed as a non-commutative analogue of Kawamata's result that all crepant resolutions are connected by flops. In this paper we prove the corresponding result for a class of canonical Gorenstein singularities which are not terminal, namely anticanonical cones over del Pezzo surfaces. More precisely, we first obtain a classification of NCCRs of anticanonical del Pezzo cones, showing that every NCCR arises from a geometric helix on the corresponding del Pezzo surface. We then prove that all such geometric helices are connected to each other by mutations, up to simple operations which include tensoring by line bundles and shifts. A crucial ingredient in our proofs is the polygons that can be associated to exceptional collections on del Pezzo surfaces following the works of Hille and Perling. We obtain some interesting observations about these polygons which may be of independent interest.
title NCCRs of cones over del Pezzo surfaces
topic Algebraic Geometry
16E35, 14F08, 14A22, 14E30
url https://arxiv.org/abs/2604.11319