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 of matrices over a field is called an involution if its square equals the identity matrix. Gustafson, Halmos, and Radjavi proved that any product of involutions in 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 .
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