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arXiv 2210.13675math.NTmath.AG
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动机的伽罗瓦下降:K3案例

Galois descent for motives: the K3 case

Angus McAndrew

摘要:

一个定理的格罗滕迪克告诉我们,如果伽罗瓦行动的泰特模的一个阿贝尔簇因素,通过一个较小的领域,然后阿贝尔簇,直到islam和有限扩张的基础上,本身是定义在较小的领域。受此启发,我们给出了一个伽罗瓦下降数据的动机$H$在一个字段通过要求伽罗瓦行动上的$\ell$ -进实现因子通过一个较小的字段。我们推测这个下降数据是有效的,也就是说,如果一个动机$H$满足上述标准,那么它本身必须下降到较小的领域。我们证明了这个猜想的K3曲面,在一些假设。这个证明是基于Madapusi-Pera将Kuga-Satake构造推广到任意特征的。

英文摘要:

A theorem of Grothendieck tells us that if the Galois action on the Tate module of an abelian variety factors through a smaller field, then the abelian variety, up to isogeny and finite extension of the base, is itself defined over the smaller field. Inspired by this, we give a Galois descent datum for a motive $H$ over a field by asking that the Galois action on an $\ell$-adic realisation factor through a smaller field. We conjecture that this descent datum is effective, that is if a motive $H$ satisfies the above criterion, then it must itself descend to the smaller field. We prove this conjecture for K3 surfaces, under some hypotheses. The proof is based on Madapusi-Pera's extension of the Kuga-Satake construction to arbitrary characteristic.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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