English

Quantifying shrinking and boundedly complete bases

Functional Analysis 2021-04-15 v1

Abstract

We investigate possible quantifications of R. C. James' classical work on bases and reflexivity of Banach spaces. By introducing new quantities measuring how far a basic sequence is from being shrinking and/or boundedly complete, we prove quantitative versions of James' famous characterisations of reflexivity in terms of bases. Furthermore, we establish quantitative versions of James' characterisations of reflexivity of Banach spaces with unconditional bases.

Keywords

Cite

@article{arxiv.2104.06497,
  title  = {Quantifying shrinking and boundedly complete bases},
  author = {Dongyang Chen and Tomasz Kania and Yingbin Ruan},
  journal= {arXiv preprint arXiv:2104.06497},
  year   = {2021}
}

Comments

16 pp

R2 v1 2026-06-24T01:08:25.022Z