Arithmetic degrees of dynamical systems over fields of characteristic zero

Fuente: arXiv
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Main Authors: Luo, Wenbin, Song, Jiarui
Format: Preprint
Published: 2024
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author Luo, Wenbin
Song, Jiarui
author_facet Luo, Wenbin
Song, Jiarui
contents In this article, we generalize the arithmetic degree and its related theory to dynamical systems defined over an arbitrary field $\mathbf{k}$ of characteristic $0$. We first consider a dynamical system $(X,f)$ over a finitely generated field $K$ over $\mathbb{Q}$, we introduce the arithmetic degrees $α(f,\cdot)$ for $\overline{K}$-points by using Moriwaki heights. We study the arithmetic dynamical degree of $(X,f)$ and establish the relative degree formula. The relative degree formula gives a proof of the fundamental inequality, that is, the upper arithmetic degree $\overlineα(f,x)$ is less than or equal to the first dynamical degree $λ_1(f)$ in this setting. By taking spread-outs, we extend the definition of arithmetic degrees to dynamical systems over the field $\mathbf k$. We demonstrate that our definition is independent of the choice of the spread-out. Moreover, in this setting, we prove certain special cases of the Kawaguchi-Silverman conjecture. A main novelty of this paper is that, we give a characterization of arithmetic degrees of "transcendental points" in the case $\mathbf{k}=\mathbb{C}$, from which we deduce that $α(f,x)=λ_1(f)$ for very general $x\in X(\mathbb{C})$ when $f$ is an endomorphism.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11982
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Arithmetic degrees of dynamical systems over fields of characteristic zero
Luo, Wenbin
Song, Jiarui
Number Theory
Algebraic Geometry
In this article, we generalize the arithmetic degree and its related theory to dynamical systems defined over an arbitrary field $\mathbf{k}$ of characteristic $0$. We first consider a dynamical system $(X,f)$ over a finitely generated field $K$ over $\mathbb{Q}$, we introduce the arithmetic degrees $α(f,\cdot)$ for $\overline{K}$-points by using Moriwaki heights. We study the arithmetic dynamical degree of $(X,f)$ and establish the relative degree formula. The relative degree formula gives a proof of the fundamental inequality, that is, the upper arithmetic degree $\overlineα(f,x)$ is less than or equal to the first dynamical degree $λ_1(f)$ in this setting. By taking spread-outs, we extend the definition of arithmetic degrees to dynamical systems over the field $\mathbf k$. We demonstrate that our definition is independent of the choice of the spread-out. Moreover, in this setting, we prove certain special cases of the Kawaguchi-Silverman conjecture. A main novelty of this paper is that, we give a characterization of arithmetic degrees of "transcendental points" in the case $\mathbf{k}=\mathbb{C}$, from which we deduce that $α(f,x)=λ_1(f)$ for very general $x\in X(\mathbb{C})$ when $f$ is an endomorphism.
title Arithmetic degrees of dynamical systems over fields of characteristic zero
topic Number Theory
Algebraic Geometry
url https://arxiv.org/abs/2401.11982