English

Weak-2-local symmetric maps on C*-algebras

Operator Algebras 2015-10-06 v1

Abstract

We introduce and study weak-2-local symmetric maps between C^*-algebras AA and BB as non necessarily linear nor continuous maps Δ:AB\Delta: A\to B such that for each a,bAa,b\in A and ϕB\phi\in B^{*}, there exists a symmetric linear map Ta,b,ϕ:ABT_{a,b,\phi}: A\to B, depending on aa, bb and ϕ\phi, satisfying ϕΔ(a)=ϕTa,b,ϕ(a)\phi \Delta(a) = \phi T_{a,b,\phi}(a) and ϕΔ(b)=ϕTa,b,ϕ(b)\phi \Delta(b) = \phi T_{a,b,\phi}(b). We prove that every weak-2-local symmetric map between C^*-algebras is a linear map. Among the consequences we show that every weak-2-local ^*-derivation on a general C^*-algebra is a (linear) ^*-derivation. We also establish a 2-local version of the Kowalski-S{\l}odkowski theorem for general C^*-algebras by proving that every 2-local ^*-homomorphism between C^*-algebras is a (linear) ^*-homomorphism.

Keywords

Cite

@article{arxiv.1510.00915,
  title  = {Weak-2-local symmetric maps on C*-algebras},
  author = {Juan Carlos Cabello and Antonio M. Peralta},
  journal= {arXiv preprint arXiv:1510.00915},
  year   = {2015}
}
R2 v1 2026-06-22T11:12:17.098Z