Local inequalities for $cA_k$ singularities

Fuente: arXiv
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Hauptverfasser: Krylov, Igor, Okada, Takuzo, Paemurru, Erik
Format: Preprint
Veröffentlicht: 2025
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author Krylov, Igor
Okada, Takuzo
Paemurru, Erik
author_facet Krylov, Igor
Okada, Takuzo
Paemurru, Erik
contents We generalize an intersection-theoretic local inequality of Fulton-Lazarsfeld to weighted blowups. As a consequence, we obtain the $4n^2/(k+1)$-inequality for isolated $cA_k$ singularities, an analogue of the $4 n^2$-inequality for smooth points. We use this to prove birational rigidity of many families of Fano 3-fold weighted complete intersections with terminal quotient singularities and isolated $cA_k$ singularities, including sextic double solids with $cA_1$ and ordinary $cA_2$ points.
format Preprint
id arxiv_https___arxiv_org_abs_2508_21676
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Local inequalities for $cA_k$ singularities
Krylov, Igor
Okada, Takuzo
Paemurru, Erik
Algebraic Geometry
14J45, 14E08, 14J30, 14C17, 14M10
We generalize an intersection-theoretic local inequality of Fulton-Lazarsfeld to weighted blowups. As a consequence, we obtain the $4n^2/(k+1)$-inequality for isolated $cA_k$ singularities, an analogue of the $4 n^2$-inequality for smooth points. We use this to prove birational rigidity of many families of Fano 3-fold weighted complete intersections with terminal quotient singularities and isolated $cA_k$ singularities, including sextic double solids with $cA_1$ and ordinary $cA_2$ points.
title Local inequalities for $cA_k$ singularities
topic Algebraic Geometry
14J45, 14E08, 14J30, 14C17, 14M10
url https://arxiv.org/abs/2508.21676