Schatten norms on Hilbert C*-modules via pure states
Abstract
Let (ℰ, ⟨ ·, ·⟩) be a Hilbert C*-module over a C*-algebra A. The space of adjointable operators on ℰ is denoted by ℒ(ℰ). The sets of all states and pure states on A are denoted by 𝒮(A) and 𝒫( A), respectively. For τ∈𝒮( A), let us define 𝒩ℰτ:={ x∈ℰ:τ( ⟨ x,x⟩)=0 }. The Hilbert completion of ℰ/𝒩ℰτ is denoted by ℰτ. For T∈ℒ(ℰ), the operator Tℰτ∈𝔹( ℰτ), is defined by Tℰτ(x+𝒩ℰτ)=Tx+𝒩ℰτ. In this paper, we show that ℰτ=ℰ/𝒩ℰτ when A either is a C*-algebra of compact operators or is commutative. We introduce a quantity in the context of Hilbert C*-modules, denoted by πℰk(·) for k≥1. We prove that πℰk(T)≤supτ∈𝒫( A)|Tℰτ|(k)≤πℰ♯k(Tℰ♯) for every T∈ℒ(ℰ), where the space ℰ♯ is constructed as the extension of ℰ by the embedding of A into its enveloping von Neumann algebra A**.
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BibTeX
@misc{abedi2026schatten,
title = {{Schatten norms on Hilbert $C^*$-modules via pure states}},
author = {Sajjad Abedi and Mohammad Sal Moslehian},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.13944},
eprint = {2609.13944},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.13944},
}
RIS
TY - UNPB
TI - Schatten norms on Hilbert C^*-modules via pure states
AU - Sajjad Abedi
AU - Mohammad Sal Moslehian
PY - 2026
DA - 2026/09/12
PB - arXiv
DO - 10.48550/arxiv.2609.13944
UR - https://arxiv.org/abs/2609.13944
AB - Let (ℰ, ⟨ ·, ·⟩) be a Hilbert C^*-module over a C^*-algebra A. The space of adjointable operators on ℰ is denoted by ℒ(ℰ). The sets of all states and pure states on A are denoted by 𝒮(A) and 𝒫( A), respectively. For τ∈𝒮( A), let us define 𝒩^ℰ_τ:={ x∈ℰ:τ( ⟨ x,x⟩)=0 }. The Hilbert completion of ℰ/𝒩^ℰ_τ is denoted by ℰ_τ. For T∈ℒ(ℰ), the operator T_ℰ_τ∈𝔹( ℰ_τ), is defined by T_ℰ_τ(x+𝒩^ℰ_τ)=Tx+𝒩^ℰ_τ. In this paper, we show that ℰ_τ=ℰ/𝒩^ℰ_τ when A either is a C^*-algebra of compact operators or is commutative. We introduce a quantity in the context of Hilbert C^*-modules, denoted by π^ℰ_k(·) for k≥1. We prove that π^ℰ_k(T)≤sup_τ∈𝒫( A)|T_ℰ_τ|_(k)≤π^ℰ^♯_k(T_ℰ^♯) for every T∈ℒ(ℰ), where the space ℰ^♯ is constructed as the extension of ℰ by the embedding of A into its enveloping von Neumann algebra A^**.
ER -