Operational 2-local automorphisms/derivations
Operator Algebras
2024-07-16 v1 Functional Analysis
Abstract
Let be a (not necessarily linear, additive or continuous) map of a standard operator algebra. Suppose for any there is an algebra automorphism of such that \begin{align*} \phi(a)\phi(b) = \theta_{a,b}(ab). \end{align*} We show that either or is a linear Jordan homomorphism. Similar results are obtained when any of the following conditions is satisfied: \begin{align*} \phi(a) + \phi(b) &= \theta_{a,b}(a+b), \\ \phi(a)\phi(b)+\phi(b)\phi(a) &= \theta_{a,b}(ab+ba), \quad\text{or} \\ \phi(a)\phi(b)\phi(a) &= \theta_{a,b}(aba). \end{align*} We also show that a map of a semi-finite von Neumann algebra is a linear derivation if for every there is a linear derivation of such that
Cite
@article{arxiv.2407.10150,
title = {Operational 2-local automorphisms/derivations},
author = {Liguang Wang and Ngai-Ching Wong},
journal= {arXiv preprint arXiv:2407.10150},
year = {2024}
}
Comments
10 pages; to appear in J. Nonlinear and Convex Analysis