Pointwise Convergence of Random Ergodic Averages at the L1 Endpoint
Abstract
In his highly influential paper, \emph{On the maximal ergodic theorem for certain subsets of the integers}, Bourgain introduced the study of pointwise convergence of ergodic averages along randomly generated subsets of the integers, developing a robust Lp-theory for p>1. More recently, this theory was partially complemented at the L1 endpoint by work of LaVictoire, who treated averages along random sequences that are ``slightly denser" than the set of squares, for which universal L1 pointwise convergence is known to fail. In this work, we prove that, almost surely, for every measure-preserving system and every integrable function, the ergodic averages formed by sampling along random sequences with quadratic growth converge almost everywhere. Our proof combines harmonic-analytic methods developed by M.~Christ with a ``random sampling" of quadratic forms, thereby overcoming the main uniformity obstruction.
Related
- Pointwise convergence of bilinear ergodic averages for commuting transformations
- Pointwise convergence of noncommutative ergodic averages along the primes
- Analysis of a zeroth-order multiscale sampler: strong convergence, convergence of ergodic averages and weak convergence
- Polynomial configurations and pointwise averages along Piatetski--Shapiro primes
- Polynomial configurations and pointwise averages along Piatetski-Shapiro sequences
BibTeX
@misc{burstein2026pointwise,
title = {{Pointwise Convergence of Random Ergodic Averages at the \(L^1\) Endpoint}},
author = {Will Burstein and Lorenzo Catani and Ben Krause},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.04106},
eprint = {2610.04106},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.04106},
}
RIS
TY - UNPB
TI - Pointwise Convergence of Random Ergodic Averages at the L^1 Endpoint
AU - Will Burstein
AU - Lorenzo Catani
AU - Ben Krause
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.04106
UR - https://arxiv.org/abs/2610.04106
AB - In his highly influential paper, \emph{On the maximal ergodic theorem for certain subsets of the integers}, Bourgain introduced the study of pointwise convergence of ergodic averages along randomly generated subsets of the integers, developing a robust L^p-theory for p>1. More recently, this theory was partially complemented at the L^1 endpoint by work of LaVictoire, who treated averages along random sequences that are ``slightly denser" than the set of squares, for which universal L^1 pointwise convergence is known to fail. In this work, we prove that, almost surely, for every measure-preserving system and every integrable function, the ergodic averages formed by sampling along random sequences with quadratic growth converge almost everywhere. Our proof combines harmonic-analytic methods developed by M.~Christ with a ``random sampling" of quadratic forms, thereby overcoming the main uniformity obstruction.
ER -