Table of Contents
Fetching ...

A Weyl equidistribution theorem over function fields

Ethan Ackelsberg

TL;DR

This work proves a function-field analogue of Weyl's equidistribution theorem and resolves a conjecture of Lê, Liu, and Wooley by showing that a polynomial sequence $P(u)=\sum_{r\in\mathcal{K}\cup\{0\}} \alpha_r u^r$ is well-distributed in the torus $\mathcal{T}$ provided there exists a $k$ with $p\nmid k$, no $p^v k$ in $\mathcal{K}$ for any $v\ge0$, and $\alpha_k\notin\mathcal{Q}$. The proof uses the Bergelson–Leibman equidistribution theorem by decomposing $P$ into additive components and exploiting an additive term with an irrational coefficient to force $\mathcal{F}(\eta)=\mathcal{T}$, yielding full equidistribution. The paper also extends the result to multivariable polynomials and discusses extensions to global function fields via integral-basis identifications, clarifying the role of Frobenius-related obstructions in positive characteristic. Overall, it provides a robust framework for equidistribution in dual groups of function-field rings and advances the understanding of when such sequences fail to be equidistributed due to characteristic-$p$ phenomena.

Abstract

A classical theorem of Weyl states that any polynomial with an irrational coefficient other than the constant term is uniformly distributed mod 1. We prove a new function field analogue of this statement, confirming a conjecture of Lê, Liu, and Wooley.

A Weyl equidistribution theorem over function fields

TL;DR

This work proves a function-field analogue of Weyl's equidistribution theorem and resolves a conjecture of Lê, Liu, and Wooley by showing that a polynomial sequence is well-distributed in the torus provided there exists a with , no in for any , and . The proof uses the Bergelson–Leibman equidistribution theorem by decomposing into additive components and exploiting an additive term with an irrational coefficient to force , yielding full equidistribution. The paper also extends the result to multivariable polynomials and discusses extensions to global function fields via integral-basis identifications, clarifying the role of Frobenius-related obstructions in positive characteristic. Overall, it provides a robust framework for equidistribution in dual groups of function-field rings and advances the understanding of when such sequences fail to be equidistributed due to characteristic- phenomena.

Abstract

A classical theorem of Weyl states that any polynomial with an irrational coefficient other than the constant term is uniformly distributed mod 1. We prove a new function field analogue of this statement, confirming a conjecture of Lê, Liu, and Wooley.

Paper Structure

This paper contains 3 sections, 7 theorems, 34 equations.

Key Result

Theorem 1.1

Let $P(n) = \alpha_d n^d + \ldots + \alpha_1 n + \alpha_0 \in \mathbb{R}[n]$. If at least one of $\alpha_1, \ldots, \alpha_d$ is irrational, then $(P(n))_{n \in \mathbb{N}}$ is uniformly distributed mod 1.

Theorems & Definitions (12)

  • Theorem 1.1: weyl
  • Theorem 1.2
  • Remark 1.3
  • Theorem 2.1: bl, Theorem 0.3
  • Remark 2.2
  • Proposition 2.3: bl
  • proof : Proof of Theorem \ref{['thm: main']}
  • Theorem 3.1
  • Theorem 3.2: bl
  • proof : Proof of Theorem \ref{['thm: multivariable']}
  • ...and 2 more