English

A remark on characterizing inner product spaces via strong three-point homogeneity

Functional Analysis 2025-12-16 v2 Metric Geometry

Abstract

We show that a normed linear space is isometrically isomorphic to an inner product space if and only if it is a strongly nn-point homogeneous metric space for any (or every) n3n \geqslant 3. The counterpart for n=2n=2 is the Banach-Mazur problem.

Keywords

Cite

@article{arxiv.2312.08106,
  title  = {A remark on characterizing inner product spaces via strong three-point homogeneity},
  author = {Sujit Sakharam Damase and Apoorva Khare},
  journal= {arXiv preprint arXiv:2312.08106},
  year   = {2025}
}

Comments

Significantly expanded, including adding details in the proof of Theorem 4; the statement of Theorem 10; and all of Section 3. Final version, 9 pages, to appear in the Canadian Mathematical Bulletin