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Main Author: Beaumont, Alonso
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.13523
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author Beaumont, Alonso
author_facet Beaumont, Alonso
contents Let $f$ be a dominant endomorphism of the projective line, which is not conjugate to a power map $z\mapsto z^{\pm d}$. We consider the centralizers of the iterates of $f$, $C(f^{n}):=\{\textrm{dominant}\;g:\mathbb{P}^{1}\rightarrow\mathbb{P}^{1}\;|\; g\circ f^{n}=f^{n}\circ g\}$, $n\geq1$, and prove that their union is equal to $C(f^{N})$ for some $N\geq1$. This solves a conjecture of F. Pakovich. As an application, we obtain a Tits alternative for cancellative semigroups of endomorphisms of the projective line, without an assumption of finite generation, extending the results of J.P. Bell, K. Huang, W. Peng and T.J. Tucker.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13523
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the centralizers of endomorphisms of the projective line
Beaumont, Alonso
Dynamical Systems
Group Theory
Number Theory
20M05, 14H37
Let $f$ be a dominant endomorphism of the projective line, which is not conjugate to a power map $z\mapsto z^{\pm d}$. We consider the centralizers of the iterates of $f$, $C(f^{n}):=\{\textrm{dominant}\;g:\mathbb{P}^{1}\rightarrow\mathbb{P}^{1}\;|\; g\circ f^{n}=f^{n}\circ g\}$, $n\geq1$, and prove that their union is equal to $C(f^{N})$ for some $N\geq1$. This solves a conjecture of F. Pakovich. As an application, we obtain a Tits alternative for cancellative semigroups of endomorphisms of the projective line, without an assumption of finite generation, extending the results of J.P. Bell, K. Huang, W. Peng and T.J. Tucker.
title On the centralizers of endomorphisms of the projective line
topic Dynamical Systems
Group Theory
Number Theory
20M05, 14H37
url https://arxiv.org/abs/2512.13523