English

The CCAP for graph products of operator algebras

Operator Algebras 2024-05-24 v2 Functional Analysis

Abstract

For a simple graph Γ\Gamma and for unital CC^*-algebras with GNS-faithful states (Av,φv)(\mathbf{A}_v,\varphi_v) for vVΓv\in V\Gamma, we consider the reduced graph product (A,φ)=v,Γ(Av,φv)(\mathcal{A},\varphi)=*_{v,\Gamma}(\mathbf{A}_{v},\varphi_v) , and show that if every CC^*-algebra Av\mathbf{A}_{v} has the completely contractive approximation property (CCAP) and satisfies some additional condition, then the graph product has the CCAP as well. The additional condition imposed is satisfied in natural cases, for example for the reduced group CC^*-algebra of a discrete group GG that possesses the CCAP. Our result is an extension of the result of Ricard and Xu in [Proposition 4.11, 25] where they prove this result under the same conditions for free products. Moreover, our result also extends the result of Reckwerdt in [Theorem 5.5, 24], where he proved for groups that weak amenability with Cowling-Haagerup constant 11 is preserved under graph products. Our result further covers many new cases coming from Hecke-algebras and discrete quantum groups.

Keywords

Cite

@article{arxiv.2211.07323,
  title  = {The CCAP for graph products of operator algebras},
  author = {Matthijs Borst},
  journal= {arXiv preprint arXiv:2211.07323},
  year   = {2024}
}

Comments

Updated to the Journal version