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arXiv 1601.04840math.COmath.NT
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关于Prouhet-Thue-Morse序列的形式逆

On formal inverse of the Prouhet-Thue-Morse sequence

Maciej Gawro, Maciej Ulas

摘要:

设$p$是素数,考虑一个$p$ -自动序列${\bf u}=(u_{n})_{n\in\N}$及其生成函数$U(X)=\sum_{n=0}^{\infty}u_{n}X^{n}\in\mathbb{F}_{p}[[X]]$ .此外,让我们假设$u_{0}=0$和$u_{1}\neq 0$,并考虑形式幂级数$V\in\mathbb{F}_{p}[[X]]$,它是$U(X)$的合成逆,即,$U(V(X))=V(U(X))=X$。本文研究了幂级数$V(X)$的系数序列的算术性质。我们主要感兴趣的情况下,当$u_{n}=t_{n}$,其中$t_{n}=s_{2}(n)\pmod{2}$和${\bf t}=(t_{n})_{n\in\N}$是Prouhet-Thue-Morse序列定义的两个字母表$\{0,1\}$。更确切地说,我们研究序列${\bf c}=(c_{n})_{n\in\N}$,这是序列${\bf t}$的生成函数的合成逆的系数序列。这个序列显然是2自动的。我们描述序列${\bf a}$表征方程$c_{n}=1$的解。特别地,我们证明了序列${\bf a}$是2-正则的。我们还证明了一个递增序列的方程$c_{n}=0$的解决方案是不$k$ -正规的任何$k$。此外,我们提出了一个结果有关的${\bf a}$序列的密度性质。

英文摘要:

Let $p$ be a prime number and consider a $p$-automatic sequence ${\bf u}=(u_{n})_{n\in\N}$ and its generating function $U(X)=\sum_{n=0}^{\infty}u_{n}X^{n}\in\mathbb{F}_{p}[[X]]$. Moreover, let us suppose that $u_{0}=0$ and $u_{1}\neq 0$ and consider the formal power series $V\in\mathbb{F}_{p}[[X]]$ which is a compositional inverse of $U(X)$, i.e., $U(V(X))=V(U(X))=X$. In this note we initiate the study of arithmetic properties of the sequence of coefficients of the power series $V(X)$. We are mainly interested in the case when $u_{n}=t_{n}$, where $t_{n}=s_{2}(n)\pmod{2}$ and ${\bf t}=(t_{n})_{n\in\N}$ is the Prouhet-Thue-Morse sequence defined on the two letter alphabet $\{0,1\}$. More precisely, we study the sequence ${\bf c}=(c_{n})_{n\in\N}$ which is the sequence of coefficients of the compositional inverse of the generating function of the sequence ${\bf t}$. This sequence is clearly 2-automatic. We describe the sequence ${\bf a}$ characterizing solutions of the equation $c_{n}=1$. In particular, we prove that the sequence ${\bf a}$ is 2-regular. We also prove that an increasing sequence characterizing solutions of the equation $c_{n}=0$ is not $k$-regular for any $k$. Moreover, we present a result concerning some density properties of a sequence related to ${\bf a}$.

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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