English

On the constant of Lipschitz approximability

Functional Analysis 2023-10-06 v2 Metric Geometry

Abstract

In this note we find λ>1\lambda>1 and give an explicit construction of a separable Banach space XX such that there is no λ\lambda-Lipschitz retraction from XX onto any compact convex subset of XX whose closed linear span is XX. This is closely related to a well-known open problem raised by Godefroy and Ozawa in 2014 and represent the first known example with such a property.

Keywords

Cite

@article{arxiv.2304.12042,
  title  = {On the constant of Lipschitz approximability},
  author = {Rubén Medina},
  journal= {arXiv preprint arXiv:2304.12042},
  year   = {2023}
}

Comments

23 pages. 4 figures. More detailed proofs

R2 v1 2026-06-28T10:15:43.581Z