activity
20232026
collaborators

6 papers

math.DS2026

Quantitative orbit equivalence for rank-one systems

Corentin Correia, Spyridon Petrakos

We prove that any two rank-one systems are sub- orbit equivalent, fully clarifying quantitative orbit equivalence for a generic class of transformations. As a corollary, we es…

math.OA2026

Topological full groups and stable rank one

David Kerr, Spyridon Petrakos

We establish stable rank one for the reduced group C-algebras of the C-simple topological full groups and dynamical alternating groups constructed by Kerr and Tucker-Drob.…

math.DS2025

Quantitative orbit equivalence for -odometers

Petr Naryshkin, Spyridon Petrakos

We prove that any two -odometers are sub--orbit equivalent, greatly strengthening previous results and giving a definitive picture of quantitative orbit equivalenc…

math.DS2024

Bauer simplices and the small boundary property

David Kerr, Grigoris Kopsacheilis, Spyridon Petrakos

We show that, for every minimal action of a countably infinite discrete group on a compact metrizable space, if the extreme boundary of the simplex of invariant Borel probability m…

math.DS2024

Almost finiteness and groups of dynamical origin

Petr Naryshkin, Spyridon Petrakos

We introduce the property of having good subgroups for actions of countable discrete groups on compact metrizable spaces, and show that it implies comparison when the acting group…

math.OA2023

McDuff factors from amenable actions and dynamical alternating groups

David Kerr, Spyridon Petrakos

Given a topologically free action of a countably infinite amenable group on the Cantor set, we prove that, for every subgroup of the topological full group containing the alter…