English

A Tauberian theorem for ideal statistical convergence

Functional Analysis 2019-08-15 v1 General Topology

Abstract

Given an ideal I\mathcal{I} on the positive integers, a real sequence (xn)(x_n) is said to be I\mathcal{I}-statistically convergent to \ell provided that {nN:1n{kn:xkU}ε}I \textstyle \left\{n \in \mathbf{N}: \frac{1}{n}|\{k \le n: x_k \notin U\}| \ge \varepsilon\right\} \in \mathcal{I} for all neighborhoods UU of \ell and all ε>0\varepsilon>0. First, we show that I\mathcal{I}-statistical convergence coincides with J\mathcal{J}-convergence, for some unique ideal J=J(I)\mathcal{J}=\mathcal{J}(\mathcal{I}). In addition, J\mathcal{J} is Borel [analytic, coanalytic, respectively] whenever I\mathcal{I} is Borel [analytic, coanalytic, resp.]. Then we prove, among others, that if I\mathcal{I} is the summable ideal {AN:aA1/a<}\{A\subseteq \mathbf{N}: \sum_{a \in A}1/a<\infty\} or the density zero ideal {AN:limn1nA[1,n]=0}\{A\subseteq \mathbf{N}: \lim_{n\to \infty} \frac{1}{n}|A\cap [1,n]|=0\} then I\mathcal{I}-statistical convergence coincides with statistical convergence. This can be seen as a Tauberian theorem which extends a classical theorem of Fridy. Lastly, we show that this is never the case if I\mathcal{I} is maximal.

Keywords

Cite

@article{arxiv.1908.04853,
  title  = {A Tauberian theorem for ideal statistical convergence},
  author = {Marek Balcerzak and Paolo Leonetti},
  journal= {arXiv preprint arXiv:1908.04853},
  year   = {2019}
}

Comments

15 pages, comments are welcome

R2 v1 2026-06-23T10:46:50.446Z