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arXiv 2404.07910math.AG
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作为三角函子的无穷远处邻近循环

Nearby cycles at infinity as a triangulated functor

Khoa Bang Pham

AI总结:

本文将 Raibaut 的无穷远处 motivic 邻近循环不变量推广为 motivic 同伦理论中的函子版本,使其能捕获无穷远处奇点的上同调信息,并证明该构造对任何基于六运算的邻近循环函子理论具有普遍适用性。

摘要:

对于多项式函数 $f \colon \mathbb{C}^n \longrightarrow \mathbb{C}$,奇点理论中众所周知(在 Thom、Pham、Verdier 等人之后),在 $\mathbb{C}$ 的某个有限子集之外,该函数是一个局部平凡的 $C^{\infty}$-纤维化。最小的这样的有限集被称为与 $f$ 相关联的分歧集,而确定分歧集是奇点理论中的一项困难任务。对于这样的函数,Raibaut 赋予了一个称为无穷远处 motivic 邻近循环的虚拟不变量。该不变量存在于某个簇的 Grothendieck 环中,并度量一般纤维与某个固定纤维的 Euler 示性数之间的差异。在这项工作中,我们证明了无穷远处 motivic 邻近循环在 motivic 同伦理论的背景下存在一个函子版本,称为无穷远处 motivic 邻近循环函子。无穷远处 motivic 邻近循环函子存在于 motives 的世界中,因此能够捕获无穷远处奇点的上同调信息(不仅仅是 Euler 示性数),并在虚拟 motives 的世界中实现为 Raibaut 的构造。此外,我们的构造具有普遍性,即它适用于任何以六运算定义的邻近循环函子理论。

英文摘要:

For a polynomial function $f \colon \mathbb{C}^n \longrightarrow \mathbb{C}$, it is well-known in singularity theory (after Thom, Pham, Verdier,...) that outside a finite subset of $\mathbb{C}$, the function is a locally trivial $C^{\infty}$-fibration. The minimal such finite set is called the bifurcation set associated with $f$ and determining the bifurcation sets is a difficult task in singularity theory. To such a function, Raibaut attaches a virtual invariant called motivic nearby cycles at infinity. This invariant lives in some Grothendieck ring of varieties and measures the difference between the Euler characteristics of the general fiber and a fixed fiber. In this work, we show that the motivic nearby cycles at infinity admits a functorial version in the context of motivic homotopy theory, called the motivic nearby cycles functors at infinity. The motivic nearby cycles functors at infinity live in the world of motives and hence capture cohomological information (not just Euler characteristics) of singularities at infinity and realizes to Raibaut's construction in the world of virtual motives. Moreover, our construction is universal in the sense that it is applicable to any theory of nearby cycles functors defined in terms of six operations.

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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