English

On extendability of functionals on Hilbert $C^*$-modules

Operator Algebras 2022-05-17 v1

Abstract

Let MNM\subset N be Hilbert CC^*-modules over a CC^*-algebra AA with M=0M^\perp=0. It was shown recently by J. Kaad and M. Skeide that there exists a non-zero AA-valued functional on NN such that its restriction onto MM is zero. Here we show that this may happen even if AA is monotone complete. On the other hand, we show that for certain type I WW^*-algebras this cannot happen.

Keywords

Cite

@article{arxiv.2205.07089,
  title  = {On extendability of functionals on Hilbert $C^*$-modules},
  author = {V. Manuilov},
  journal= {arXiv preprint arXiv:2205.07089},
  year   = {2022}
}

Comments

9 pages

R2 v1 2026-06-24T11:17:24.173Z