Lie $n$-centralizers of von Neumann algebras

TL;DR

This paper characterizes Lie $n$-centralizers on von Neumann algebras, showing they are essentially linear maps plus a central additive map that vanishes on certain Lie products, and applies this to generalized Lie $n$-derivations.

Contribution

It provides a complete description of Lie $n$-centralizers on von Neumann algebras and characterizes generalized Lie $n$-derivations in this setting.

Findings

Lie $n$-centralizers are of the form $ ext{W}A + ext{ extbeta}(A)$ with $W$ central

The additive map $ extbeta$ vanishes on specific Lie products involving the projection $P$

Application to the characterization of generalized Lie $n$-derivations

Abstract

Let $\U$ be a von Neumann algebra with a projection $P\in \U$. For any $A_1,A_2,\ldots,A_n\in\U,$ define $p_1(A_1)=A_1,$ $p_n (A_1,A_2,\ldots,A_n)=[p_{n-1} (A_1,A_2,\ldots,A_{n-1}),A_n]$ for all integers $n\geq 2,$ where $[A,B]=AB-BA$ $(A,B\in\U)$ denotes the usual Lie product. Assume that $\phi:\U\to\U$ is an additive mapping satisfying \[\phi(p_n(A_1, A_2, \ldots, A_n)) = p_n(\phi(A_1), A_2, \ldots, A_n) = p_n(A_1, \phi(A_2), \ldots, A_n) \] for all $A_1, A_2, \ldots, A_n \in \U$ with $A_1A_2=P$ In this article, it is shown that the map $\phi$ is of the form $\phi(A)=WA+\xi(A)$ for all $A\in \U$, where $W\in \mathrm{Z}(\U)$, and $\xi:\U \to \Z(\U)$ ($\Z(\U)$ is the center of $\U$) is an additive map such that $\xi(p_n(A_1, A_2, \ldots, A_n) )=0$ for any $A_1, A_2, \ldots, A_n \in \U$ with $A_1A_2=P$. As an application, we characterize generalized Lie $n$-derivations on arbitrary von Neumann algebras.