Hausdorff dimension of recurrence sets for matrix transformations of tori
Zhangnan Hu, Bing Li
Abstract
Let $T\colon\mathbb{T}^d\to \mathbb{T}^d$, defined by $T x=Ax(\bmod 1)$, where $A$ is a $d\times d$ integer matrix with eigenvalues $1<|λ_1|\le|λ_2|\le\dots\le|λ_d|$. We investigate the Hausdorff dimension of the recurrence set \[R(ψ):=\{x\in\mathbb{T}^d\colon T^nx\in B(x,ψ(n)) {\rm ~for~infinitely~ many~}n\}\] for $α\ge\log|λ_d/λ_1|$, where $ψ$ is a positive decreasing function defined on $\mathbb{N}$ and its lower order at infinity is $α=\liminf\limits_{n\to\infty}\frac{-\log ψ(n)}{n}$. In the case that $A$ is diagonalizable over $\mathbb{Q}$ with integral eigenvalues, we obtain the dimension formula.
