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arXiv math/0406404math.MG
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Frechet度量嵌入法的局限性

Limitations to Frechet's Metric Embedding Method

Yair Batal, Nathan Linial, Manor Mendel, Assaf Naor

摘要:

Frechet的经典等距嵌入的论点已经发展成为一个主要的工具,在研究度量空间。Frechet嵌入的一个重要例子是Bourgain嵌入。作者最近证明了对于每个e>0,任何n点度量空间都包含一个大小至少为n^(1-e)的子集,它嵌入到l_2中,失真为O(\log(2/e)/e)。我们使用的嵌入是非弗雷歇的,本文的目的是表明这不是巧合。具体地说,对于每个e>0,我们构造任意大的n点度量空间,使得在至少为n^{1/2 + e}的子集上嵌入到l_p中的任何Frechet的失真是Ω((\log n)^{1/p})。

英文摘要:

Frechet's classical isometric embedding argument has evolved to become a major tool in the study of metric spaces. An important example of a Frechet embedding is Bourgain's embedding. The authors have recently shown that for every e>0 any n-point metric space contains a subset of size at least n^(1-e) which embeds into l_2 with distortion O(\log(2/e) /e). The embedding we used is non-Frechet, and the purpose of this note is to show that this is not coincidental. Specifically, for every e>0, we construct arbitrarily large n-point metric spaces, such that the distortion of any Frechet embedding into l_p on subsets of size at least n^{1/2 + e} is Ω((\log n)^{1/p}).

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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