Products of extended binomial coefficients and their partial factorizations

Fuente: arXiv
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Auteurs principaux: Du, Lara, Lagarias, Jeffrey, Yangjit, Wijit
Format: Preprint
Publié: 2021
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author Du, Lara
Lagarias, Jeffrey
Yangjit, Wijit
author_facet Du, Lara
Lagarias, Jeffrey
Yangjit, Wijit
contents This paper studies properties of the integer sequence $\overline{\overline{G}}_n=\prod_{k=0}^n\binom{n}{k}_{\mathbb{Z},\mathbb{N}}$ which is analogous to $\overline{G}_n=\prod_{k=0}^n\binom{n}{k}$, the product of the elements of the $n$-th row of Pascal's triangle. Here $\binom{n}{k}_{\mathbb{Z},\mathbb{N}}$ is an extended binomial coefficient, defined in the paper, constructed using an extended version of M. Bhargava's theory of generalized factorials. In 1996 M. Bhargava introduced a generalization of the factorial function, $n!_S=\prod_pν_n(S,p)$ in terms of their prime factorization, and defines associated binomial coefficients. The last two authors extended Bhargava's invariants further to define such invariants attached to each integer $b\ge2$. One obtains extended factorials and extended binomial coefficients, and the maximal extension defines extended factorials $n!_{\mathbb{Z},\mathbb{N}}=\prod_{b\ge2}b^{α_n(\mathbb{Z},b)}$ including all $b\ge2$, with associated extended binomial coefficients $\binom{n}{k}_{\mathbb{Z},\mathbb{N}}$, yielding $\overline{\overline{G}}_n$. We have $\overline{\overline{G}}_n=\prod_{b=2}^nb^{\overlineν(n,b)}$ and the partial factorizations $\overline{\overline{G}}(n,x)=\prod_{b=2}^{\lfloor x\rfloor}b^{\overlineν(n,b)}$. This paper shows $\log\overline{\overline{G}}(n,αn)$ is well approximated by $f_{\overline{\overline{G}}}(α)n^2\log n+g_{\overline{\overline{G}}}(α)n^2$ as $n\to\infty$ for limit functions $f_{\overline{\overline{G}}}(α)$ and $g_{\overline{\overline{G}}}(α)$ defined for all $0\leα\le1$. The remainder term has a power saving in $n$. The main results are deduced from study of functions $\overline{A}(n,x)$ and $\overline{B}(n,x)$ that encode statistics of the base $b$ radix expansions of the integer $n$ (and smaller integers), where the base $b$ ranges over all integers $2\le b\le x$.
format Preprint
id arxiv_https___arxiv_org_abs_2112_14422
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Products of extended binomial coefficients and their partial factorizations
Du, Lara
Lagarias, Jeffrey
Yangjit, Wijit
Number Theory
11B65, 11B83, 11N37
This paper studies properties of the integer sequence $\overline{\overline{G}}_n=\prod_{k=0}^n\binom{n}{k}_{\mathbb{Z},\mathbb{N}}$ which is analogous to $\overline{G}_n=\prod_{k=0}^n\binom{n}{k}$, the product of the elements of the $n$-th row of Pascal's triangle. Here $\binom{n}{k}_{\mathbb{Z},\mathbb{N}}$ is an extended binomial coefficient, defined in the paper, constructed using an extended version of M. Bhargava's theory of generalized factorials. In 1996 M. Bhargava introduced a generalization of the factorial function, $n!_S=\prod_pν_n(S,p)$ in terms of their prime factorization, and defines associated binomial coefficients. The last two authors extended Bhargava's invariants further to define such invariants attached to each integer $b\ge2$. One obtains extended factorials and extended binomial coefficients, and the maximal extension defines extended factorials $n!_{\mathbb{Z},\mathbb{N}}=\prod_{b\ge2}b^{α_n(\mathbb{Z},b)}$ including all $b\ge2$, with associated extended binomial coefficients $\binom{n}{k}_{\mathbb{Z},\mathbb{N}}$, yielding $\overline{\overline{G}}_n$. We have $\overline{\overline{G}}_n=\prod_{b=2}^nb^{\overlineν(n,b)}$ and the partial factorizations $\overline{\overline{G}}(n,x)=\prod_{b=2}^{\lfloor x\rfloor}b^{\overlineν(n,b)}$. This paper shows $\log\overline{\overline{G}}(n,αn)$ is well approximated by $f_{\overline{\overline{G}}}(α)n^2\log n+g_{\overline{\overline{G}}}(α)n^2$ as $n\to\infty$ for limit functions $f_{\overline{\overline{G}}}(α)$ and $g_{\overline{\overline{G}}}(α)$ defined for all $0\leα\le1$. The remainder term has a power saving in $n$. The main results are deduced from study of functions $\overline{A}(n,x)$ and $\overline{B}(n,x)$ that encode statistics of the base $b$ radix expansions of the integer $n$ (and smaller integers), where the base $b$ ranges over all integers $2\le b\le x$.
title Products of extended binomial coefficients and their partial factorizations
topic Number Theory
11B65, 11B83, 11N37
url https://arxiv.org/abs/2112.14422