English

A note on asymptotically monotone basic sequences and well-separated sets

Functional Analysis 2019-04-18 v2

Abstract

We remark that if XX is an infinite dimensional Banach space then every seminormalized weakly null sequence in XX has an asymptotic monotone basic subsequence. We also observe that if XX contains an isomorphic copy of 1\ell_1, then for every ε>0\varepsilon>0 there exist a (1+ε)(1 +\varepsilon)-equivalent norm \vertiii\vertiii{\cdot} on XX such that the unit sphere (S(X,\vertiii))(S_{(X, \vertiii{\cdot})}) contains a normalized bimonotone basic sequences which is symmetrically 22-separated.

Keywords

Cite

@article{arxiv.1902.10857,
  title  = {A note on asymptotically monotone basic sequences and well-separated sets},
  author = {Cleon S. Barroso},
  journal= {arXiv preprint arXiv:1902.10857},
  year   = {2019}
}

Comments

9 pages, comments are more than welcome. Corrected version

R2 v1 2026-06-23T07:53:42.859Z