Characterization of self-affine tile digit sets on $\mathbb{R}^n$

Abstract

Let $R$ be an $n\times n$ expanding matrix with integral entries. A fundamental question in the fractal tiling theory is to understand the structure of the digit set $\mathcal{D}\subset\mathbb{Z}^n$ so that the integral self-affine set $T(R,\mathcal{D})$ is a translational tile on $\mathbb{R}^n$ In this paper, we introduce a notion of skew-product-form digit set which is a very general class of tile digit sets. Especially, we show that in the one-dimensional case, if $T(b,\mathcal{D})$ is a self-similar tile, then there exists $m\geq 1$ such that $$\mathcal{D}_m=\mathcal{D}+b\mathcal{D}+\cdots+b^{m-1}\mathcal{D}$$ is a skew-product-form digit set. Notice that $T(b,\mathcal{D})=T(b^m,\mathcal{D}_m)$, in some sense, we completely characterize the self-similar tiles in $\mathbb{R}^1$ As an application, we establish that all self-similar tiles $T(b,\mathcal{D})$ where $b=p^αq^β$ contains at most two prime factors are spectral sets in $\mathbb{R}^1$.

Theorems & Definitions (20)

• Definition 1.1
• Remark 1.2
• Theorem 1.1
• Example 1.3: LW1996-3
• Lemma 1.4
• Example 1.5: LR2003
• Example 1.6: LLR2017
• Theorem 1.2
• Conjecture 1.7
• Corollary 1.8