English

A uniform ergodic theorem for some N\"orlund means

Spectral Theory 2021-03-22 v1

Abstract

We obtain a uniform ergodic theorem for the sequence 1s(n)k=0n(Δs)(nk)Tk\frac1{s(n)} \sum_{k=0}^n(\varDelta s)(n-k)\,T^k, where Δ\varDelta is the inverse of the endomorphism on the vector space of scalar sequences which maps each sequence into the sequence of its partial sums, TT is a bounded linear operator on a Banach space and ss is a divergent nondecreasing sequence of strictly positive real numbers, such that limn+s(n+1)/s(n)=1\lim_{n\rightarrow+\infty} s(n+1)/s(n)=1 and Δqs1\varDelta^qs\in\ell_1 for some positive integer qq. Indeed, we prove that if Tn/s(n)T^n/s(n) converges to zero in the uniform operator topology, then the sequence of averages above converges in the same topology if and only if 1 is either in the resolvent set of TT, or a simple pole of the resolvent function of TT.

Keywords

Cite

@article{arxiv.2103.10732,
  title  = {A uniform ergodic theorem for some N\"orlund means},
  author = {Laura Burlando},
  journal= {arXiv preprint arXiv:2103.10732},
  year   = {2021}
}
R2 v1 2026-06-24T00:20:58.737Z