English

Asymptotic limits, Banach limits, and Ces\`aro means

Functional Analysis 2020-10-29 v1

Abstract

Every new inner product in a Hilbert space is obtained from the original one by means of a unique positive operator.. The first part of the paper is a survey on applications of such a technique, including a characterization of similarity to isometries.. The second part focuses on Banach limits for dealing with power bounded operators. It is shown that if a power bounded operator for which the sequence of shifted Ces\`aro means converges (at least in the weak topology) uniformly in the shift parameter, then it has a Ces\`aro asymptotic limit coinciding with its φ\varphi-asymptotic limit for all Banach limits φ\varphi.

Keywords

Cite

@article{arxiv.2010.14740,
  title  = {Asymptotic limits, Banach limits, and Ces\`aro means},
  author = {C. S. Kubrusly and B. P. Duggal},
  journal= {arXiv preprint arXiv:2010.14740},
  year   = {2020}
}
R2 v1 2026-06-23T19:42:21.207Z