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An example related to the slicing inequality for general measures

Metric Geometry 2017-08-24 v3 Functional Analysis

Abstract

For nNn\in \mathbb{N} let SnS_n be the smallest number S>0S>0 satisfying the inequality KfSK1nmaxξSn1Kξf \int_K f \le S \cdot |K|^{\frac 1n} \cdot \max_{\xi\in S^{n-1}} \int_{K\cap \xi^\bot} f for all centrally-symmetric convex bodies KK in Rn\mathbb{R}^n and all even, continuous probability densities ff on KK. Here K|K| is the volume of KK. It was proved by the second-named author that Sn2nS_n\le 2\sqrt{n}, and in analogy with Bourgain's slicing problem, it was asked whether SnS_n is bounded from above by a universal constant. In this note we construct an example showing that Sncn/loglogn,S_n\ge c\sqrt{n}/\sqrt{\log \log n}, where c>0c > 0 is an absolute constant. Additionally, for any 0<α<20 < \alpha < 2 we describe a related example that satisfies the so-called ψα\psi_{\alpha}-condition.

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Cite

@article{arxiv.1706.01132,
  title  = {An example related to the slicing inequality for general measures},
  author = {Bo'az Klartag and Alexander Koldobsky},
  journal= {arXiv preprint arXiv:1706.01132},
  year   = {2017}
}

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22 pages