Weak mixing and non-recurrence along finitely generated multiplicative semigroups of β
Abstract
Let π« be a finite nonempty set of primes, and let Sπ« be the multiplicative semigroup that they generate. We prove that there are an invertible weakly mixing measure-preserving transformation T and a set A of positive measure such that Aβ© TβrA=β for every rβ Sπ«. This gives a negative answer to Bergelson's 1996 question concerning recurrence along {2m3n:m,nβ₯1}, and applies to every finitely generated multiplicative semigroup of positive integers. More generally, we give a sufficient condition for weakly mixing non-recurrence based on divisibility properties and separation by finitely many rotations of the circle. This criterion also applies to an infinitely generated multiplicative semigroup not contained in any Sπ« with π« finite.
Related
- Irreducibility of Endomorphisms of Finitely Generated Free Semigroups
- The free multiplicative Lie algebra L(P) for a finitely generated parafree group P
- Systems of equations with elements of finitely generated groups and with linear recurrence sequences
- Ordering the space of finitely generated groups
- Conjugator length in finitely generated groups
BibTeX
@misc{liu2026weak,
title = {{Weak mixing and non-recurrence along finitely generated multiplicative semigroups of $\mathbb N$}},
author = {Zhuowei Liu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.33710},
eprint = {2610.33710},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.33710},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Weak mixing and non-recurrence along finitely generated multiplicative semigroups of β
AU - Zhuowei Liu
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.33710
UR - https://arxiv.org/abs/2610.33710
AB - Let π« be a finite nonempty set of primes, and let S_π« be the multiplicative semigroup that they generate. We prove that there are an invertible weakly mixing measure-preserving transformation T and a set A of positive measure such that Aβ© T^βrA=β
for every rβ S_π«. This gives a negative answer to Bergelson's 1996 question concerning recurrence along {2^m3^n:m,nβ₯1}, and applies to every finitely generated multiplicative semigroup of positive integers. More generally, we give a sufficient condition for weakly mixing non-recurrence based on divisibility properties and separation by finitely many rotations of the circle. This criterion also applies to an infinitely generated multiplicative semigroup not contained in any S_π« with π« finite.
ER -