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arXiv 1012.3387math.CO
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关于$k$ -抛物子空间排列的实补的同调

On the Homology of the Real Complement of the $k$-Parabolic Subspace Arrangement

Christopher Severs, Jacob A. White

摘要:

本文研究了$k$ -抛物排列,它是任意有限实反射群的$k$ -相等排列的推广.当$k=2$,这些安排对应于充分研究的Coxeter安排。我们构造了一个胞腔复形$Perm_k(W)$,是同伦等价的补充。然后,我们应用离散莫尔斯理论,以获得一个最小的胞腔复形的补体。结果给出了贝蒂数的组合解释,并证明了同调群是无挠的.我们还研究了图的独立复形的一个推广,并证明了当图是森林时,这个推广是可壳的。这一结果被用于研究$Perm_k(W)$使用离散的莫尔斯理论。

英文摘要:

In this paper, we study $k$-parabolic arrangements, a generalization of the $k$-equal arrangement for any finite real reflection group. When $k=2$, these arrangements correspond to the well-studied Coxeter arrangements. We construct a cell complex $Perm_k(W)$ that is homotopy equivalent to the complement. We then apply discrete Morse theory to obtain a minimal cell complex for the complement. As a result, we give combinatorial interpretations for the Betti numbers, and show that the homology groups are torsion free. We also study a generalization of the Independence Complex of a graph, and show that this generalization is shellable when the graph is a forest. This result is used in studying $Perm_k(W)$ using discrete Morse theory.

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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