Index of coregularity zero log Calabi-Yau pairs

Fuente: arXiv
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Autores principales: Filipazzi, Stefano, Mauri, Mirko, Moraga, Joaquín
Formato: Preprint
Publicado: 2022
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author Filipazzi, Stefano
Mauri, Mirko
Moraga, Joaquín
author_facet Filipazzi, Stefano
Mauri, Mirko
Moraga, Joaquín
contents In this article, we study the index of log Calabi--Yau pairs $(X,B)$ of coregularity 0. We show that $2λ(K_X+B)\sim 0$, where $λ$ is the Weil index of $(X,B)$. This is in contrast to the case of klt Calabi--Yau varieties, where the index can grow doubly exponentially with the dimension. Our sharp bound on the index extends to the context of generalized log Calabi--Yau pairs, semi-log canonical pairs, and isolated log canonical singularities of coregularity 0. As a consequence, we show that the index of a variety appearing in the Gross--Siebert program or in the Kontsevich--Soibelman program is at most $2$. Finally, we discuss applications to Calabi--Yau varieties endowed with a finite group action, including holomorphic symplectic varieties endowed with a purely non-symplectic automorphism.
format Preprint
id arxiv_https___arxiv_org_abs_2209_02925
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Index of coregularity zero log Calabi-Yau pairs
Filipazzi, Stefano
Mauri, Mirko
Moraga, Joaquín
Algebraic Geometry
14B05, 14E30, 14L24, 14M25 (Primary), 14A20, 53D20 (Secondary)
In this article, we study the index of log Calabi--Yau pairs $(X,B)$ of coregularity 0. We show that $2λ(K_X+B)\sim 0$, where $λ$ is the Weil index of $(X,B)$. This is in contrast to the case of klt Calabi--Yau varieties, where the index can grow doubly exponentially with the dimension. Our sharp bound on the index extends to the context of generalized log Calabi--Yau pairs, semi-log canonical pairs, and isolated log canonical singularities of coregularity 0. As a consequence, we show that the index of a variety appearing in the Gross--Siebert program or in the Kontsevich--Soibelman program is at most $2$. Finally, we discuss applications to Calabi--Yau varieties endowed with a finite group action, including holomorphic symplectic varieties endowed with a purely non-symplectic automorphism.
title Index of coregularity zero log Calabi-Yau pairs
topic Algebraic Geometry
14B05, 14E30, 14L24, 14M25 (Primary), 14A20, 53D20 (Secondary)
url https://arxiv.org/abs/2209.02925