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arXiv 2301.09002math.AT
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流形上 $S^3$-作用的 Gysin 辫

The Gysin braid for $S^3$-actions on manifolds

José Ignacio Royo Prieto, Martintxo Saralegi-Aranguren

AI总结:

针对非半自由的 $\mathbb S^3$ 光滑作用,本文构造联系 $M$ 的上同调与轨道空间相交上同调的 Gysin 辫,并揭示其依赖于 $M^{\mathbb S^1}$ 相交上同调的奇异项。

摘要:

给定球面 $\mathbb S^3$ 在流形 $M$ 上的一个光滑作用,我们此前已经构造了一个 Gysin 序列,将流形 $M$ 的上同调与轨道空间 $M/\mathbb S^3$ 的上同调联系起来。该序列包含一个依赖于子集 $M^{\mathbb S^1}$ 的奇异项。注意,轨道空间是一个分层伪流形,即一类可应用相交上同调的奇异空间。在作用为半自由的情形下,第一作者已经构造了一个 Gysin 序列,将 $M$ 的上同调与 $M/\mathbb S^3$ 的相交上同调联系起来。如果作用不是半自由的,会发生什么?这正是本工作的目标。情形更为复杂,我们找到的不是 Gysin 序列,而是一个将 $M$ 的上同调与 $M/\mathbb S^3$ 的相交上同调联系起来的 Gysin 辫。该辫同样包含一个奇异项,而这一次该项依赖于 $M^{\mathbb S^1}$ 的相交上同调。

英文摘要:

Given a smooth action of the sphere $\mathbb S^3$ on a manifold $M$, we have previously constructed a Gysin sequence relating the cohomology of the manifold $M$ and that of the orbit space $M/\mathbb S^3$. This sequence involves an exotic term depending on the subset $M^{\mathbb S^1}$. Notice that the orbit space is a stratified pseudomanifold, a kind of singular spaces where intersection cohomology applies. In the case where the the action is semi-free, the first author has already constructed a Gysin sequence relating the cohomology of $M$ and the intersection cohomology of $M/\mathbb S^3$. What happens if the action is not semi-free? This is the goal of this work. The situation is more complicated and we do not find a Gysin sequence but a Gysin braid relating the cohomology of $M$ and the intersection cohomology of $M/\mathbb S^3$. This braid also contains an exotic term depending this time on the intersection cohomology of $M^{\mathbb S^1}$.

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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