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arXiv 1909.08253math.DSmath.NT
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一个改进Dirichlet定理的动力学Borel-Cantelli引理

A dynamical Borel-Cantelli lemma via improvements to Dirichlet's theorem

Dmitry Kleinbock, Shucheng Yu

摘要:

令$X\cong \operatorname{SL}_2(\mathbb R)/\operatorname{SL}_2(\mathbb Z)$为$\mathbb R^2$中的么模格空间,对于任何$r\ge 0$,用$K_r\subset X$表示格集,使得其所有非零向量至少具有上确界范数$e^{-r}$。这些是$X$的紧凑嵌套子集,其中$K_0 = {\bigcap}_{r}K_r$是两个封闭的horcycle的并集。我们使用一个显式的二阶矩公式的西格尔变换的指示功能的平方$\mathbb R^2$在原点为中心的体积集$K_r$作为$r\to 0$导出一个渐近公式。结合Kleinbock和Wadleigh建立的$ψ$-Dirichlet数集的0 - 1定律,给出了$X$上关于收缩目标族$\{K_r\}$的测地线流的一个新的动力学Borel-Cantelli引理.

英文摘要:

Let $X\cong \operatorname{SL}_2(\mathbb R)/\operatorname{SL}_2(\mathbb Z)$ be the space of unimodular lattices in $\mathbb R^2$, and for any $r\ge 0$ denote by $K_r\subset X$ the set of lattices such that all its nonzero vectors have supremum norm at least $e^{-r}$. These are compact nested subset{s} of $X$, with $K_0 = {\bigcap}_{r}K_r$ being the union of two closed horocycles. We use an explicit second moment formula for the Siegel transform of the indicator functions of squares in $\mathbb R^2$ centered at the origin to derive an asymptotic formula for the volume of sets $K_r$ as $r\to 0$. Combined with a zero-one law for the set of the $ψ$-Dirichlet numbers established by Kleinbock and Wadleigh, this gives a new dynamical Borel-Cantelli lemma for the geodesic flow on $X$ with respect to the family of shrinking targets $\{K_r\}$.

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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