English

Preservers of Operator Commutativity

Operator Algebras 2024-09-12 v1 Functional Analysis

Abstract

Let M\mathfrak{M} and J\mathfrak{J} be JBW^*-algebras admitting no central summands of type I1I_1 and I2,I_2, and let Φ:MJ\Phi: \mathfrak{M} \rightarrow \mathfrak{J} be a linear bijection preserving operator commutativity in both directions, that is, [x,M,y]=0[Φ(x),J,Φ(y)]=0,[x,\mathfrak{M},y] = 0 \Leftrightarrow [\Phi(x),\mathfrak{J},\Phi(y)] = 0, for all x,yMx,y\in \mathfrak{M}, where the associator of three elements a,b,ca,b,c in M\mathfrak{M} is defined by [a,b,c]:=(ab)c(cb)a[a,b,c]:=(a\circ b)\circ c - (c\circ b)\circ a. We prove that under these conditions there exist a unique invertible central element z0z_0 in J\mathfrak{J}, a unique Jordan isomorphism J:MJJ: \mathfrak{M} \rightarrow \mathfrak{J}, and a unique linear mapping β\beta from M\mathfrak{M} to the centre of J\mathfrak{J} satisfying Φ(x)=z0J(x)+β(x), \Phi(x) = z_0 \circ J(x) + \beta(x), for all xM.x\in \mathfrak{M}. Furthermore, if Φ\Phi is a symmetric mapping (i.e., Φ(x)=Φ(x)\Phi (x^*) = \Phi (x)^* for all xMx\in \mathfrak{M}), the element z0z_0 is self-adjoint, JJ is a Jordan ^*-isomorphism, and β\beta is a symmetric mapping too. In case that J\mathfrak{J} is a JBW^*-algebra admitting no central summands of type I1I_1, we also address the problem of describing the form of all symmetric bilinear mappings B:J×JJB : \mathfrak{J}\times \mathfrak{J}\to \mathfrak{J} whose trace is associating (i.e., [B(a,a),b,a]=0,[B(a,a),b,a] = 0, for all a,bJ)a, b \in \mathfrak{J}) providing a complete solution to it. We also determine the form of all associating linear maps on J\mathfrak{J}.

Keywords

Cite

@article{arxiv.2409.06799,
  title  = {Preservers of Operator Commutativity},
  author = {Gerardo M. Escolano and Antonio M. Peralta and Armando R. Villena},
  journal= {arXiv preprint arXiv:2409.06799},
  year   = {2024}
}
R2 v1 2026-06-28T18:40:23.764Z