English

Classification of abelian finite-dimensional $C^*$-algebras by orthogonality

Functional Analysis 2024-11-05 v1 Operator Algebras

Abstract

The main goal of the article is to prove that if A1\mathcal A_1 and A2\mathcal A_2 are Birkhoff-James isomorphic CC^*-algebras over the fields F1\mathbb F_1 and F2\mathbb F_2, respectively and if A1\mathcal A_1 finite-dimensional, abelian of dimension greater than one, then F1=F2\mathbb F_1=\mathbb F_2 and A1\mathcal A_1 and A2\mathcal A_2 are (isometrically) \ast-isomorphic CC^*-algebras. Furthermore, it is also proved that for a finite-dimensional CC^*-algebra A\mathcal A, we have LA\mathcal L_{\mathcal A}^\bot is the sum of minimal ideals which are not skew-fields and LA\mathcal L_{\mathcal A}^{\bot\bot} is the sum of minimal ideals which are skew-fields, where LA\mathcal L_{\mathcal A} denotes the set of all left-symmetric elements in A\mathcal A and for any subset SA\mathcal S\subseteq \mathcal A, the set S\mathcal S^\bot represents the set of all elements of A\mathcal A which are Birkhoff-James orthogonal to S\mathcal S. A procedure to extract the minimal ideals which are (commutative) fields is also given.

Keywords

Cite

@article{arxiv.2411.01684,
  title  = {Classification of abelian finite-dimensional $C^*$-algebras by orthogonality},
  author = {Bojan Kuzma and Sushil Singla},
  journal= {arXiv preprint arXiv:2411.01684},
  year   = {2024}
}