English

Linear maps preserving product of involutions

Functional Analysis 2026-03-19 v3 Group Theory Operator Algebras Rings and Algebras

Abstract

An element of the algebra Mn(F)M_n(\mathbb{F}) of n×nn \times n matrices over a field F\mathbb{F} is called an involution if its square equals the identity matrix. Gustafson, Halmos, and Radjavi proved that any product of involutions in Mn(F)M_n(\mathbb{F}) can be expressed as a product of at most four involutions. In this article, we investigate the bijective linear preservers of the sets of products of two, three, or four involutions in Mn(F)M_n(\mathbb{F}).

Keywords

Cite

@article{arxiv.2504.14198,
  title  = {Linear maps preserving product of involutions},
  author = {Chi-Kwong Li and Tejbir Lohan and Sushil Singla},
  journal= {arXiv preprint arXiv:2504.14198},
  year   = {2026}
}

Comments

v3, 25 pages. Minor revision following referee report. Improved exposition; arguments clarified. Revised Propositions 2.1, 2.2, and 3.2. Added proof of Lemma 2.4; corrected proof of Lemma 2.5