Local Derivations on Subalgebras of τ-Measurable Operators with Respect to Semi-finite von Neumann Algebras

Abstract

This paper is devoted to local derivations on subalgebras on the algebra $S(M, \tau)$ of all $\tau$-measurable operators affiliated with a von Neumann algebra $M$ without abelian summands and with a faithful normal semi-finite trace $\tau.$ We prove that if $\mathcal{A}$ is a solid $\ast$-subalgebra in $S(M, \tau)$ such that $p\in \mathcal{A}$ for all projection $p\in M$ with finite trace, then every local derivation on the algebra $\mathcal{A}$ is a derivation. This result is new even in the case standard subalgebras on the algebra $B(H)$ of all bounded linear operators on a Hilbert space $H.$ We also apply our main theorem to the algebra $S_0(M, \tau)$ of all $\tau$-compact operators affiliated with a semi-finite von Neumann algebra $M$ and with a faithful normal semi-finite trace $\tau.$