Self-similar groups and finite Gelfand pairs

We study the Basilica group \(B\), the iterated monodromy group \(I\) of the complex polynomial \(z^2+i\) and the Hanoi Towers group \(H^{(3)}\). The first two groups act on the binary rooted tree, the third one on the ternary rooted tree. We prove that the action of \(B, I\) and \(H^{(3)}\) on each...

Full description

Saved in:
Bibliographic Details
Date:2018
Main Authors: D’Angeli, Daniele, Donno, Alfredo
Format: Article
Language:English
Published: Lugansk National Taras Shevchenko University 2018
Subjects:
Online Access:https://admjournal.luguniv.edu.ua/index.php/adm/article/view/843
Tags: Add Tag
No Tags, Be the first to tag this record!
Journal Title:Algebra and Discrete Mathematics

Institution

Algebra and Discrete Mathematics
Description
Summary:We study the Basilica group \(B\), the iterated monodromy group \(I\) of the complex polynomial \(z^2+i\) and the Hanoi Towers group \(H^{(3)}\). The first two groups act on the binary rooted tree, the third one on the ternary rooted tree. We prove that the action of \(B, I\) and \(H^{(3)}\) on each level is 2-points homogeneous with respect to the ultrametric distance. This gives rise to symmetric Gelfand pairs: we then compute the corresponding spherical functions. In the case of \(B\) and \(H^{(3)}\) this result can also be obtained by using the strong property that the rigid stabilizers of the vertices of the first level of the tree act spherically transitively on the respective subtrees. On the other hand, this property does not hold in the case of \(I\).