arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2109.00261math.AT
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再探单纯交同调

Simplicial intersection homology revisited

David Chataur, Martin Saralegi-Aranguren, Daniel Tanré

AI总结:

本文直接证明了单纯与奇异交链复形间的典范映射是拟同构,并将该平行性扩展至交爆破上同调,证明了伪流形与 PL 空间中该上同调的同构性质及可计算性。

摘要:

交同调可基于单纯链、奇异链和 PL 链定义,且已知在完整过滤单纯复形上这三种版本同构。文献中,交同调奇异与单纯情形间的同构以 PL 情形作为中介。这里我们直接证明单纯与奇异交链复形间的典范映射是拟同构。这类似于单纯复形的经典证明,其论证基于残余复形概念而非骨架。单纯与奇异方法的这种平行性也扩展到了我们先前工作中引入的交爆破上同调。对于可定向伪流形,得益于与基本类的帽积,该上同调对任意系数环均具有与交同调的 Poincaré 同构。因此,伪流形的爆破交上同调可由三角剖分计算。最后,我们引入了 PL 空间的爆破交上同调,并证明其与奇异上同调同构。

英文摘要:

Intersection homology is defined for simplicial, singular and PL chains and it is well known that the three versions are isomorphic for a full filtered simplicial complex. In the literature, the isomorphism, between the singular and the simplicial situations of intersection homology, uses the PL case as an intermediate. Here we show directly that the canonical map between the simplicial and the singular intersection chains complexes is a quasi-isomorphism. This is similar to the classical proof for simplicial complexes, with an argument based on the concept of residual complex and not on skeletons. This parallel between simplicial and singular approaches is also extended to the intersection blown-up cohomology that we introduced in a previous work. In the case of an orientable pseudomanifold, this cohomology owns a Poincaré isomorphism with the intersection homology, for any coefficient ring, thanks to a cap product with a fundamental class. So, the blown-up intersection cohomology of a pseudomanifold can be computed from a triangulation. Finally, we introduce a blown-up intersection cohomology for PL spaces and prove that it is isomorphic to the singular one.

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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