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arXiv 2402.00862math.AGmath.NT
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代数叠的墨菲定律

Murphy's Law for Algebraic Stacks

Daniel Bragg, Max Lieblich

AI总结:

该研究证明曲线叠等多种自然代数几何模叠满足“代数叠墨菲定律”,即域上所有Deligne-Mumford gerbe都可作为其点的剩余gerbe,对应对象以所有可能方式无法在模域定义、粗模空间无法成为精细模空间,核心依赖等变射影几何构造向相对几何的推广。

摘要:

我们证明了多种自然的代数几何模叠(包括曲线叠)具有如下性质:域上的每个Deligne-Mumford(德利涅-芒福德)gerbe(叠化广群)都可作为其某一点的剩余gerbe出现。这些gerbe是叠的对象无法在其模域上定义、以及对应粗模空间无法成为精细模空间的普适障碍。因此,我们的结果表明,许多自然模叠中存在的对象,会以所有可能的方式受到阻碍而无法在其模域上定义,且它们的粗空间也会以所有可能的方式无法成为精细模空间。支撑我们论证的一个核心洞见是,等变射影几何中的许多经典构造可推广到域上任意Deligne-Mumford gerbe的相对几何情形。

英文摘要:

We show that various natural algebro-geometric moduli stacks, including the stack of curves, have the property that every Deligne-Mumford gerbe over a field appears as the residual gerbe of one of their points. These gerbes are universal obstructions for objects of the stack to be defined over their fields of moduli, and for the corresponding coarse moduli space to be fine. Thus, our results show that many natural moduli stacks hold objects that are obstructed from being defined over their fields of moduli in every possible way, and have coarse spaces which fail to be fine moduli spaces in every possible way. A basic insight enabling our arguments is that many classical constructions in equivariant projective geometry generalize to the setting of relative geometry over an arbitrary Deligne-Mumford gerbe over a field.

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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