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arXiv 2402.08331math.NTcs.DMcs.FLmath.COmath.LO
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二次无理数下的Beatty序列:可判定性及其应用

Beatty Sequences for a Quadratic Irrational: Decidability and Applications

Luke Schaeffer, Jeffrey Shallit, Stefan Zorcic

AI总结:

本文研究二次无理数下的Beatty序列的同步性,证明其可判定性,并应用该结果解决加法基的判定问题,同时解决Reble和Kimberling的开放问题。

摘要:

令α和β属于同一二次域。我们证明了不相等的Beatty序列(⌊nα+β⌋)_n≥1是同步的,即存在一个有限自动机,其输入为n和y的Ostrowski表示,并在y=⌊nα+β⌋时接受。由于已知基于二次数的Ostrowski表示的加法关系是可计算的,因此得出结论:这些序列的加法理论的一阶逻辑理论是可判定的。决策过程可轻松在自由软件Walnut中实现。作为应用,我们证明对于每个r≥1,判定集合{⌊nα+β⌋:n≥1}是否为加法基(或渐近加法基)的阶数r是可判定的。使用我们的技术,我们还解决了一些Reble和Kimberling的开放问题,并给出了Hildebrand等人序列的显式特征化。

英文摘要:

Let $α$ and $β$ belong to the same quadratic field. We show that the inhomogeneous Beatty sequence $(\lfloor n α+ β\rfloor)_{n \geq 1}$ is synchronized, in the sense that there is a finite automaton that takes as input the Ostrowski representations of $n$ and $y$ in parallel, and accepts if and only if $y = \lfloor n α+ β\rfloor$. Since it is already known that the addition relation is computable for Ostrowski representations based on a quadratic number, a consequence is a new and rather simple proof that the first-order logical theory of these sequences with addition is decidable. The decision procedure is easily implemented in the free software Walnut. As an application, we show that for each $r \geq 1$ it is decidable whether the set $\{ \lfloor n α+ β\rfloor \, : \, n \geq 1 \}$ forms an additive basis (or asymptotic additive basis) of order $r$. Using our techniques, we also solve some open problems of Reble and Kimberling, and give an explicit characterization of a sequence of Hildebrand et al.

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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