English

On preservers of strong Birkhoff-James orthogonality between $C^*$-algebras

Operator Algebras 2025-10-29 v1

Abstract

It is shown that every linear strong Birkhoff-James isomorphism between unital CC^*-algebras is a *-isomorphism followed by a unitary multiplication. Moreover, as a partial extension of this result to the non-unital case, the form of (possibly nonlinear) strong Birkhoff-James isomorphisms between compact CC^*-algebras are determined. A nonlinear characterization of compact CC^*-algebras in terms of strong Birkhoff-James orthogonality is also given.

Keywords

Cite

@article{arxiv.2510.24308,
  title  = {On preservers of strong Birkhoff-James orthogonality between $C^*$-algebras},
  author = {Bojan Kuzma and Srdjan Stefanović and Ryotaro Tanaka},
  journal= {arXiv preprint arXiv:2510.24308},
  year   = {2025}
}