English

Uniqueness of a topological Furstenberg system

Dynamical Systems 2026-03-31 v1

Abstract

Given a semigroup GG and a bounded function f:GCf: G \to \mathbb{C}, a topological Furstenberg system of ff is a topological dynamical system X=(X,(Tg)gG)\mathbb{X}=(X, (T_g)_{g \in G}) that encodes the dynamical behaviour of ff. We show that X\mathbb{X} is unique up to topological isomorphism, thus providing a topological analogue of the measurable case established by Bergelson and Ferr\'e Moragues for amenable semigroups. We also provide necessary and sufficient conditions for subsets of a group to have isomorphic Furstenberg systems. In addition, we study sets with minimal Furstenberg systems and identify them as a special subclass of dynamically syndetic sets. Moreover, we use this notion to obtain a new characterization of sets of topological recurrence.

Keywords

Cite

@article{arxiv.2603.27899,
  title  = {Uniqueness of a topological Furstenberg system},
  author = {Ioannis Kousek and Vicente Saavedra-Araya},
  journal= {arXiv preprint arXiv:2603.27899},
  year   = {2026}
}

Comments

26 pages. Comments welcome!