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arXiv 2402.07779math.DSmath.CO
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在某些类别的顺从群中寻找积集

Finding product sets in some classes of amenable groups

Dimitrios Charamaras, Andreas Mountakis

AI总结:

本文将关于自然数大子集中和集的 Erdős 猜想扩展至虚幂零群等顺从群,证明正上 Banach 密度子集必含移位积集,并引入平方绝对连续性,回答了相关综述中的多个问题。

摘要:

2022年,Kra、Moreira、Richter 和 Robertson 利用遍历理论的方法,解决了 Erdős 关于自然数大子集中和集的一个长期存在的猜想。在本文中,我们将此结果扩展到几个重要的顺从群类别,包括所有有限生成的虚幂零群,以及所有满足子群 $2G := \{g+g : g\in G\}$ 具有有限指标这一性质的阿贝尔群 $(G,+)$。我们证明,在上述类别中的任意群 $G$ 中,任何具有正上 Banach 密度的 $A\subset G$ 都包含移位积集,其形式为 $\{tb_ib_j\colon i<j\}$,对应于某个无限序列 $(b_n)_{n\in\mathbb{N}}$ 和某个 $t\in G$。事实上,我们对所有具备一种我们称之为平方绝对连续性这一性质的顺从群证明了该结果。我们的结果为 Kra、Moreira、Richter 和 Robertson 在最近的一篇综述中提出的几个问题与猜想提供了答案。

英文摘要:

In 2022, using methods from ergodic theory, Kra, Moreira, Richter, and Robertson resolved a longstanding conjecture of Erdős about sumsets in large subsets of the natural numbers. In this paper, we extend this result to several important classes of amenable groups, including all finitely generated virtually nilpotent groups, and all abelian groups $(G,+)$ with the property that the subgroup $2G := \{g+g : g\in G\}$ has finite index. We prove that in any group $G$ from the above classes, any $A\subset G$ with positive upper Banach density contains a shifted product set of the form $\{tb_ib_j\colon i<j\}$, for some infinite sequence $(b_n)_{n\in\mathbb{N}}$ and some $t\in G$. In fact, we show this result for all amenable groups that posses a property which we call square absolute continuity. Our results provide answers to several questions and conjectures posed in a recent survey of Kra, Moreira, Richter and Robertson.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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