English

A missing theorem on dual spaces

Functional Analysis 2024-05-13 v3 Classical Analysis and ODEs Operator Algebras

Abstract

We answer in the affirmative the surprisingly difficult questions: If a complex Banach space possesses a real predual X, then is X a complex Banach space? If a complex Banach space possesses a real predual, then does it have a complex predual? We also answer the analogous questions for operator spaces, that is spaces of operators on a Hilbert space, up to complete isometry. Indeed we use operator space methods to solve the Banach space question above.

Keywords

Cite

@article{arxiv.2405.01133,
  title  = {A missing theorem on dual spaces},
  author = {David P. Blecher},
  journal= {arXiv preprint arXiv:2405.01133},
  year   = {2024}
}

Comments

Error in early lemma (Proposition 2.3) endangers Theorem 4.1. Result is valid assuming the conclusions of Proposition 2.3 for the map q in Theorem 4.1

R2 v1 2026-06-28T16:13:44.952Z