Isometries between C$^*$-algebras with finite corank

Michiya Mori

Isometries between C$^*$-algebras with finite corank

Operator Algebras 2026-07-15 v1 Functional Analysis

Authors: Michiya Mori

Abstract

We give a characterization of linear isometries with finite corank between two arbitrary unital C $^*$ -algebras in terms of Jordan $^*$ -homomorphisms and ``finite-dimensional remainders''. Also, the corresponding results are given for linear isometries and linear order embeddings between self-adjoint parts of C $^*$ -algebras. In the finite-dimensional case, we give new examples of linear isometries between matrix algebras.

Keywords

isometries C*-algebras finite corank Jordan *-homomorphisms order embeddings

Cite

@article{arxiv.2607.13367,
  title  = {Isometries between C$^*$-algebras with finite corank},
  author = {Michiya Mori},
  journal= {arXiv preprint arXiv:2607.13367},
  year   = {2026}
}

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32 pages