A realisation result for moduli spaces of group actions on the line

Fuente: arXiv
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Autori principali: Brum, Joaquín, Bon, Nicolás Matte, Rivas, Cristóbal, Triestino, Michele
Natura: Preprint
Pubblicazione: 2023
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author Brum, Joaquín
Bon, Nicolás Matte
Rivas, Cristóbal
Triestino, Michele
author_facet Brum, Joaquín
Bon, Nicolás Matte
Rivas, Cristóbal
Triestino, Michele
contents Given a finitely generated group $G$, the possible actions of $G$ on the real line (without global fixed points), considered up to semi-conjugacy, can be encoded by the space of orbits of a flow on a compact space $(Y, Φ)$ naturally associated with $G$ and uniquely defined up to flow equivalence, that we call the \emph{Deroin space} of $G$. We show a realisation result: every expansive flow $(Y, Φ)$ on a compact metrisable space of topological dimension 1, satisfying some mild additional assumptions, arises as the Deroin space of a finitely generated group. This is proven by identifying the Deroin space of an explicit family of groups acting on suspension flows of subshifts, which is a variant of a construction introduced by the second and fourth authors. This result provides a source of examples of finitely generated groups satisfying various new phenomena for actions on the line, related to their rigidity/flexibility properties and to the structure of (path-)connected components of the space of actions.
format Preprint
id arxiv_https___arxiv_org_abs_2306_03846
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A realisation result for moduli spaces of group actions on the line
Brum, Joaquín
Bon, Nicolás Matte
Rivas, Cristóbal
Triestino, Michele
Group Theory
Dynamical Systems
Given a finitely generated group $G$, the possible actions of $G$ on the real line (without global fixed points), considered up to semi-conjugacy, can be encoded by the space of orbits of a flow on a compact space $(Y, Φ)$ naturally associated with $G$ and uniquely defined up to flow equivalence, that we call the \emph{Deroin space} of $G$. We show a realisation result: every expansive flow $(Y, Φ)$ on a compact metrisable space of topological dimension 1, satisfying some mild additional assumptions, arises as the Deroin space of a finitely generated group. This is proven by identifying the Deroin space of an explicit family of groups acting on suspension flows of subshifts, which is a variant of a construction introduced by the second and fourth authors. This result provides a source of examples of finitely generated groups satisfying various new phenomena for actions on the line, related to their rigidity/flexibility properties and to the structure of (path-)connected components of the space of actions.
title A realisation result for moduli spaces of group actions on the line
topic Group Theory
Dynamical Systems
url https://arxiv.org/abs/2306.03846