﻿ 周二代数与复动力系统讨论班：奥斯陆大学Fei Hu主讲-清华大学求真书院

### 周二代数与复动力系统讨论班：奥斯陆大学Fei Hu主讲

An upper bound for polynomial log-volume growth of automorphisms of zero entropy

Abstract

Let f by an automorphism of zero entropy of a smooth projective variety X. The polynomial log-volume growth plov(f) of f is a natural analog of Gromov's log-volume growth of automorphisms (of positive entropy), formally introduced by Cantat and Paris-Romaskevich for slow dynamics in 2020. A surprising fact noticed by Lin, Oguiso, and Zhang in 2021 is that this dynamical invariant plov(f) essentially coincides with the Gelfand–Kirillov dimension of the twisted homogeneous coordinate ring associated with (X, f), introduced by Artin, Tate, and Van den Bergh in the 1990s. It was conjectured by them that plov(f) is bounded above by d^2, where d = dim X.

We prove an upper bound for plov(f) in terms of the dimension d of X and another fundamental invariant k of (X, f) (i.e., the degree growth rate of iterates f^n with respect to an arbitrary ample divisor on X). As a corollary, we prove the above conjecture based on an earlier work of Dinh, Lin, Oguiso, and Zhang. This is joint work with Chen Jiang.

Speaker

I am a Postdoctoral Fellow at University of Oslo. My research is on Several Complex Variables, Logic and Operator algebras.

I’m working with Tuyen Trung Truong on his conjectures extending Weil’s Riemann Hypothesis to the context of dynamical systems.

I got my PhD from the National University of Singapore in 2017 and thereafter spent three years in Canada as a postdoc at the University of British Columbia, the Pacific Institute for the Mathematical Sciences, and the University of Waterloo.

Prior to that, I was studying Astronomy and Mathematics in Nanjing University.

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