Bloch's conjecture for (anti-)autoequivalences on K3 surfaces

Fuente: arXiv
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Autori principali: Li, Zhiyuan, Yu, Xun, Zhang, Ruxuan
Natura: Preprint
Pubblicazione: 2023
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author Li, Zhiyuan
Yu, Xun
Zhang, Ruxuan
author_facet Li, Zhiyuan
Yu, Xun
Zhang, Ruxuan
contents In this paper, we investigate Bloch's conjecture for autoequivalence on K3 surfaces. We introduce the notion of reflective autoequivalence of twisted K3 surfaces and prove Bloch's conjecture for such autoequivalences, thereby confirming the conjecture for all (anti-)symplectic autoequivalences of K3 surfaces with Picard number at least $3$. The main idea is that we find a Cartan-Dieudonné type decomposition of (anti)-symplectic autoequivalences. Our findings have several interesting consequences. Firstly, we verify Bloch's conjecture for (anti-)symplectic birational automorphisms of Bridgeland moduli space on a K3 surface with Picard number at least $3$. This notably implies that Bloch's conjecture holds for (anti)-symplectic birational automorphisms of finite order ($\neq 2,4$) on arbitrary hyper-Kähler varieties of $K3^{[n]}$-type. Secondly, we extend Huybrechts' work in \cite{Huy12} to twisted K3 surfaces. This extension enables us to affirm Bloch's conjecture for symplectic birational automorphisms on any hyper-Kähler variety of $K3^{[n]}$-type preserving a birational Lagrangian fibration. Finally, we prove the constant cycle property for the fixed loci of anti-symplectic involutions on hyper-Kähler varieties of $K3^{[n]}$-type, provided that $n \leq 2$ or the invariant sublattice has rank greater than $1$.
format Preprint
id arxiv_https___arxiv_org_abs_2305_10078
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Bloch's conjecture for (anti-)autoequivalences on K3 surfaces
Li, Zhiyuan
Yu, Xun
Zhang, Ruxuan
Algebraic Geometry
14J28, 14F08, 14J42
In this paper, we investigate Bloch's conjecture for autoequivalence on K3 surfaces. We introduce the notion of reflective autoequivalence of twisted K3 surfaces and prove Bloch's conjecture for such autoequivalences, thereby confirming the conjecture for all (anti-)symplectic autoequivalences of K3 surfaces with Picard number at least $3$. The main idea is that we find a Cartan-Dieudonné type decomposition of (anti)-symplectic autoequivalences. Our findings have several interesting consequences. Firstly, we verify Bloch's conjecture for (anti-)symplectic birational automorphisms of Bridgeland moduli space on a K3 surface with Picard number at least $3$. This notably implies that Bloch's conjecture holds for (anti)-symplectic birational automorphisms of finite order ($\neq 2,4$) on arbitrary hyper-Kähler varieties of $K3^{[n]}$-type. Secondly, we extend Huybrechts' work in \cite{Huy12} to twisted K3 surfaces. This extension enables us to affirm Bloch's conjecture for symplectic birational automorphisms on any hyper-Kähler variety of $K3^{[n]}$-type preserving a birational Lagrangian fibration. Finally, we prove the constant cycle property for the fixed loci of anti-symplectic involutions on hyper-Kähler varieties of $K3^{[n]}$-type, provided that $n \leq 2$ or the invariant sublattice has rank greater than $1$.
title Bloch's conjecture for (anti-)autoequivalences on K3 surfaces
topic Algebraic Geometry
14J28, 14F08, 14J42
url https://arxiv.org/abs/2305.10078