A high-codimensional Yuan's inequality and its application to higher arithmetic degrees

Jiarui Song

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arXiv · 2306.11591

A high-codimensional Yuan's inequality and its application to higher arithmetic degrees

Jiarui Song

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Abstract

In this article, we consider a dominant rational self-map $f:X \dashrightarrow X$ of a normal projective variety defined over a number field. We study the arithmetic degree $\alpha_k(f)$ for $f$ and $\alpha_k(f,V)$ of a subvariety $V$, which generalize the classical arithmetic degree $\alpha_1(f,P)$ of a point $P$. We generalize Yuan's arithmetic version of Siu's inequality to higher codimensions and utilize it to demonstrate the existence of the arithmetic degree $\alpha_k(f)$. Furthermore, we establish the relative degree formula $\alpha_k(f)=\max\{\lambda_k(f),\lambda_{k-1}(f)\}$. In addition, we prove several basic properties of the arithmetic degree $\alpha_k(f, V)$ and establish the upper bound $\overline{\alpha}_{k+1}(f, V)\leq \max\{\lambda_{k+1}(f),\lambda_{k}(f)\}$, which generalizes the classical result $\overline{\alpha}_f(P)\leq \lambda_1(f)$. Finally, we discuss a generalized version of the Kawaguchi-Silverman conjecture that was proposed by Dang et al, and we provide a counterexample to this conjecture.

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Jiarui Song. 2023-06-20. A high-codimensional Yuan's inequality and its application to higher arithmetic degrees. https://arxiv.org/abs/2306.11591

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