与 Basilica 群相关的图的谱性质

basilica 群 Schreier 图的谱性质

Spectral properties of the Schreier graphs of the basilica group

本文研究 basilica 群 Schreier 图上拉普拉斯算子的谱性质，通过建立新的递归框架计算特征多项式，揭示了简单动力学系统并证明了 KNS 谱测度的逼近结果。

On the Basilica Operation

Inspired by the Basilica group $\mathcal B$, we describe a general construction which allows us to associate to any group of automorphisms $G \leq \operatorname{Aut}(T)$ of a rooted tree $T$ a family of Basilica groups $\operatorname{Bas}_s(G), s \in \mathbb{N}_+$. For the dyadic odometer $\mathcal{O}_2$, one has $\mathcal B = \operatorname{Bas}_2(\mathcal{O}_2)$. We study which properties of groups acting on rooted trees are preserved under this operation. Introducing some techniques for handling $\operatorname{Bas}_s(G)$, in case $G$ fulfills some branching conditions, we are able to calcula…

Schreier graphs of the Basilica group

With any self-similar action of a finitely generated group $G$ of automorphisms of a regular rooted tree $T$ can be naturally associated an infinite sequence of finite graphs $\{Γ_n\}_{n\geq 1}$, where $Γ_n$ is the Schreier graph of the action of $G$ on the $n$-th level of $T$. Moreover, the action of $G$ on $\partial T$ gives rise to orbital Schreier graphs $Γ_ξ$, $ξ\in \partial T$. Denoting by $ξ_n$ the prefix of length $n$ of the infinite ray $ξ$, the rooted graph $(Γ_ξ,ξ)$ is then the limit of the sequence of finite rooted graphs $\{(Γ_n,ξ_n)\}_{n\geq 1}$ in the sense of pointed Gromov-Hau…

二次PCF多项式绝对伽罗华群的定居元素

Settled Elements in Arboreal Galois Groups of Quadratic PCF Polynomials

研究二次PCF多项式迭代单子群的定居性质，证明其在数域中存在无限多个参数使对应的树形伽罗华表示密集定居。