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

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 $k\in\mathbb{N}^+$.