English

Lower bound for cyclic sums with one-sided maximal averages in denominators

Classical Analysis and ODEs 2022-10-04 v1

Abstract

Let x=(x1,,xn)\mathbf{x}=(x_1,\dots,x_n) be an nn-tuple of positive real numbers and the sequence (xi)iZ(x_i)_{i\in\mathbb{Z}} be its nn-periodic extension. Given an nn-tuple r=(r1,,rn)\mathbf{r}=(r_1,\dots,r_n) of positive integers, let aia_i be the arithmetic mean of xi+1,,xi+rix_{i+1},\dots,x_{i+r_i}. We form the cyclic sums Sn(x,r)=i=1nxi/aiS_n(\mathbf{x},\mathbf{r})=\sum_{i=1}^n x_i/a_{i}, following the pattern of the long studied Shapiro sums, which correspond to all ri=2r_i=2, and more general Diananda sums, where all rir_i are equal. We find the asymptotics of the r\mathbf{r}-independent lower bounds An,=infrinfxSn(x,r)A_{n,*}=\inf_{\mathbf{r}}\inf_{\mathbf{x}} S_n(\mathbf{x},\mathbf{r}) as nn\to\infty: it is An,=elognA+O(1/logn)A_{n,*}=e\log n - A+O(1/\log n).

Keywords

Cite

@article{arxiv.2210.00360,
  title  = {Lower bound for cyclic sums with one-sided maximal averages in denominators},
  author = {Sergey Sadov},
  journal= {arXiv preprint arXiv:2210.00360},
  year   = {2022}
}

Comments

21 pages, 1 table, 1 figure