English

Uniqueness of completions and related topics

Functional Analysis 2018-02-27 v1 Metric Geometry

Abstract

A bounded subset of a normed linear space is said to be (diametrically) complete if it cannot be enlarged without increasing the diameter. A complete super set of a bounded set KK having the same diameter as KK is called a completion of KK. In general, a bounded set may have different completions. We study normed linear spaces having the property that there exists a nontrivial segment with a unique completion. It turns out that this property is strictly weaker than the property that each complete set is a ball, and it is strictly stronger than the property that each set of constant width is a ball. Extensions of this property are also discussed.

Keywords

Cite

@article{arxiv.1802.09133,
  title  = {Uniqueness of completions and related topics},
  author = {Chan He and Horst Martini and Senlin Wu},
  journal= {arXiv preprint arXiv:1802.09133},
  year   = {2018}
}