Integer tile and Spectrality of Cantor-Moran measures with equidifferent digit sets

TL;DR

This paper investigates conditions under which Cantor-Moran measures with equidifferent digit sets are spectral, linking spectrality to the integer tiling property of certain derived sets and providing conditions for equivalence.

Contribution

It establishes a necessary and sufficient condition for the integer tile property of derived sets and explores its relation to the spectrality of Cantor-Moran measures.

Findings

$ extbf{D}_k$ is an integer tile iff the sequence $ extbf{s}_i$ are all distinct.

$ extbf{D}_k$ being an integer tile is necessary for the measure to be spectral.

Under additional assumptions, spectrality is equivalent to $ extbf{D}_k$ being an integer tile.

Abstract

Let $\left\{b_{k}\right\}_{k=1}^{\infty}$ be a sequence of integers with $|b_{k}|\geq2$ and $\left\{D_{k}\right\}_{k=1}^{\infty} $ be a sequence of equidifferent digit sets with $D_{k}=\left\{0,1, \cdots, N-1\right\}t_{k},$ where $N\geq2$ is a prime number and $\{t_{k}\}_{k=1}^{\infty}$ is bounded. In this paper, we study the existence of the Cantor-Moran measure $\mu_{\{b_k\},\{D_k\}}$ and show that $$\mathbf{D}_k:=D_k\oplus b_{k} D_{k-1}\oplus b_{k}b_{k-1} D_{k-2}\oplus\cdots\oplus b_{k}b_{k-1}\cdots b_2D_{1}$$ is an integer tile for all $k\in\mathbb{N}^+$ if and only if $\mathbf{s}_i\neq\mathbf{s}_j$ for all $i\neq j\in\mathbb{N}^{+}$, where $\mathbf{s}_i$ is defined as the numbers of factor $N$ in $\frac{b_1b_2\cdots b_i}{Nt_i}$. Moreover, we prove that $\mathbf{D}_k$ being an integer tile for all $k\in\mathbb{N}^+$ is a necessary condition for the Cantor-Moran measure to be a spectral measure, and we provide an example to demonstrate that it cannot become a sufficient condition. Furthermore, under some additional assumptions, we establish that the Cantor-Moran measure to be a spectral measure is equivalent to $\mathbf{D}_k$ being an integer tile for all $k\in\mathbb{N}^+$.