English

Complex structures on twisted Hilbert spaces

Functional Analysis 2015-11-19 v1

Abstract

We investigate complex structures on twisted Hilbert spaces, with special attention paid to the Kalton-Peck Z2Z_2 space and to the hyperplane problem. We consider (nontrivial) twisted Hilbert spaces generated by centralizers obtained from an interpolation scale of K\"othe function spaces. We show there are always complex structures on the Hilbert space that cannot be extended to the twisted Hilbert space. If, however, the scale is formed by rearrangement invariant K\"othe function spaces then there are complex structures on it that can be extended to a complex structure of the twisted Hilbert space. Regarding the hyperplane problem we show that no complex structure on 2\ell_2 can be extended to a complex structure on an hyperplane of Z2Z_2 containing it.

Cite

@article{arxiv.1511.05867,
  title  = {Complex structures on twisted Hilbert spaces},
  author = {Jesús M. F. Castillo and Wilson Cuellar and Valentin Ferenczi and Yolanda Moreno},
  journal= {arXiv preprint arXiv:1511.05867},
  year   = {2015}
}
R2 v1 2026-06-22T11:48:36.956Z