English

Asymptotic geometry and delta-points

Functional Analysis 2022-03-29 v1

Abstract

We study Daugavet- and Δ\Delta-points in Banach spaces. A norm one element xx is a Daugavet-point (respectively a Δ\Delta-point) if in every slice of the unit ball (respectively in every slice of the unit ball containing xx) you can find another element of distance as close to 22 from xx as desired. In this paper we look for criteria and properties ensuring that a norm one element is not a Daugavet- or Δ\Delta-point. We show that asymptotically uniformly smooth spaces and reflexive asymptotically uniformly convex spaces do not contain Δ\Delta-points. We also show that the same conclusion holds true for the James tree space as well as for its predual. Finally we prove that there exists a superreflexive Banach space with a Daugavet- or Δ\Delta-point provided there exists such a space satisfying a weaker condition.

Keywords

Cite

@article{arxiv.2203.14528,
  title  = {Asymptotic geometry and delta-points},
  author = {Trond A. Abrahamsen and Vegard Lima and André Martiny and Yoël Perreau},
  journal= {arXiv preprint arXiv:2203.14528},
  year   = {2022}
}

Comments

29 pages

R2 v1 2026-06-24T10:27:55.797Z