Extreme points of unital completely positive maps invariant under partial action

Fuente: arXiv
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Autori principali: Kulkarni, Chaitanya J., Hossain, Md Amir
Natura: Preprint
Pubblicazione: 2025
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author Kulkarni, Chaitanya J.
Hossain, Md Amir
author_facet Kulkarni, Chaitanya J.
Hossain, Md Amir
contents The classical Choquet theorem establishes a barycentric decomposition for elements in a compact convex subset of a locally convex topological vector space. This decomposition is achieved through a probability measure that is supported on the set of extreme points of the subset. In this work, we consider a partial action $τ$ of a group $G$ on a $C^\ast$-algebra $\mathcal{A}$. For a fixed Hilbert space $\mathcal{H}$, we consider the set of all unital completely positive maps from $\mathcal{A}$ to $\mathcal{B}(\mathcal{H})$ that are invariant under the partial action $τ$. This set forms a compact convex subset of a locally convex topological vector space. To complete the picture of the barycentric decomposition provided by the classical Choquet theorem, we characterize the set of extreme points of this set.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20797
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extreme points of unital completely positive maps invariant under partial action
Kulkarni, Chaitanya J.
Hossain, Md Amir
Operator Algebras
46A55, 46B22, 46L55, 46L08, 47L07
The classical Choquet theorem establishes a barycentric decomposition for elements in a compact convex subset of a locally convex topological vector space. This decomposition is achieved through a probability measure that is supported on the set of extreme points of the subset. In this work, we consider a partial action $τ$ of a group $G$ on a $C^\ast$-algebra $\mathcal{A}$. For a fixed Hilbert space $\mathcal{H}$, we consider the set of all unital completely positive maps from $\mathcal{A}$ to $\mathcal{B}(\mathcal{H})$ that are invariant under the partial action $τ$. This set forms a compact convex subset of a locally convex topological vector space. To complete the picture of the barycentric decomposition provided by the classical Choquet theorem, we characterize the set of extreme points of this set.
title Extreme points of unital completely positive maps invariant under partial action
topic Operator Algebras
46A55, 46B22, 46L55, 46L08, 47L07
url https://arxiv.org/abs/2507.20797