The Dynamical Degrees of Rational Surface Automorphisms

Fuente: arXiv
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Main Author: Kim, Kyounghee
Format: Preprint
Published: 2022
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_version_ 1866914738655461376
author Kim, Kyounghee
author_facet Kim, Kyounghee
contents The induced action on the Picard group of a rational surface automorphism with positive entropy can be identified with an element of the Coxeter group associated to $E_n, n\ge 10$ diagram. It follows that the set of dynamical degrees of rational surface automorphisms is a subset of the spectral radii of elements in the Coxeter group. This article concerns the realizability of an element of the Coxeter group as an automorphism on a rational surface with an irreducible reduced anti-canonical curve. For any unrealizable element, we explicitly construct a realizable element with the same spectral radius. Hence, we show that the set of dynamical degrees and the set of spectral radii of the Coxeter group are, in fact, identical. This has been shown by Uehara in \cite{Uehara:2010} by explicitly constructing a rational surface automorphism. This construction depends on a decomposition of an element of the Coxeter group. Our proof is conceptual and provides a simple description of elements of the Coxeter group, which are realized by automorphisms on anti-canonical rational surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2211_09662
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle The Dynamical Degrees of Rational Surface Automorphisms
Kim, Kyounghee
Dynamical Systems
37F15, 37F99, 14E07
The induced action on the Picard group of a rational surface automorphism with positive entropy can be identified with an element of the Coxeter group associated to $E_n, n\ge 10$ diagram. It follows that the set of dynamical degrees of rational surface automorphisms is a subset of the spectral radii of elements in the Coxeter group. This article concerns the realizability of an element of the Coxeter group as an automorphism on a rational surface with an irreducible reduced anti-canonical curve. For any unrealizable element, we explicitly construct a realizable element with the same spectral radius. Hence, we show that the set of dynamical degrees and the set of spectral radii of the Coxeter group are, in fact, identical. This has been shown by Uehara in \cite{Uehara:2010} by explicitly constructing a rational surface automorphism. This construction depends on a decomposition of an element of the Coxeter group. Our proof is conceptual and provides a simple description of elements of the Coxeter group, which are realized by automorphisms on anti-canonical rational surfaces.
title The Dynamical Degrees of Rational Surface Automorphisms
topic Dynamical Systems
37F15, 37F99, 14E07
url https://arxiv.org/abs/2211.09662