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arXiv 2006.15569math.CAmath.MG
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关于Furstenberg集的填充维数

On the packing dimension of Furstenberg sets

Pablo Shmerkin

AI总结:

本研究证明了满足特定直线相交维数条件的平面集(含$\alpha$-Furstenberg集)的填充维数下界,结合已有结果改进了全参数范围内的平凡估计,并推广至一般直线族,揭示相关尺度的稀疏性。

摘要:

我们证明:若$\alpha\in (0,1/2]$,则对于平面$\mathbb{R}^2$中的集合$E$,若存在一个维数为1的直线族,其中每条直线与$E$的交集的维数都不小于$\alpha$,那么$E$的填充维数至少为$1/2+\alpha+c(\alpha)$,其中$c(\alpha)>0$。这一结论尤其适用于$\alpha$-Furstenberg集,即在每个方向上都至少存在一条直线,使得该集合与这条直线的Hausdorff维数不小于$\alpha$的集合。结合T. Orponen此前的结果,对于所有$\alpha\in (0,1)$,本研究改进了$\alpha$-Furstenberg集填充维数的“平凡”估计。该证明可推广到更一般的直线族,并且表明:若$\alpha$-Furstenberg集存在某些尺度使其表现得接近维数$1/2+\alpha$的集合,那么这些尺度是相当稀疏的。

英文摘要:

We prove that if $α\in (0,1/2]$, then the packing dimension of a set $E\subset\mathbb{R}^2$ for which there exists a set of lines of dimension $1$ intersecting $E$ in dimension $\ge α$ is at least $1/2+α+c(α)$ for some $c(α)>0$. In particular, this holds for $α$-Furstenberg sets, that is, sets having intersection of Hausdorff dimension $\geα$ with at least one line in every direction. Together with an earlier result of T. Orponen, this provides an improvement for the packing dimension of $α$-Furstenberg sets over the "trivial" estimate for all values of $α\in (0,1)$. The proof extends to more general families of lines, and shows that the scales at which an $α$-Furstenberg set resembles a set of dimension close to $1/2+α$, if they exist, are rather sparse.

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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