Duality for operator systems with generating cones

Fuente: arXiv
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Main Authors: Jia, Yu-Shu, Ng, Chi-Keung
Format: Preprint
Published: 2025
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author Jia, Yu-Shu
Ng, Chi-Keung
author_facet Jia, Yu-Shu
Ng, Chi-Keung
contents Let $S$ be a complete operator system with a generating cone; i.e. $S_\sa = S_+ - S_+$. We show that there is a matrix norm on the dual space $S^*$, under which, and the usual dual matrix cone, $S^*$ becomes a dual operator system with a generating cone, denoted by $S^\rd$. The canonical complete order isomorphism $ι_{S^*}: S^* \to S^\rd$ is a dual Banach space isomorphism. Furthermore, we construct a canonical completely contractive weak$^*$-homeomorphism $β_S: (S^\rd)^\rd\to S^{**}$, and verify that it is a complete order isomorphism. For a complete operator system $T$ with a generating cone and a completely positive complete contraction $φ:S\to T$, there is a weak$^*$-continuous completely positive complete contraction $φ^\rd:T^\rd \to S^\rd$ with $ι_{S^*}\circ φ^* = φ^\rd \circ ι_{T^*}$. This produces a faithful functor from the category of complete operator systems with generating cones (where morphisms are completely positive complete contractions) to the category of dual operator systems with generating cones (where morphisms are weak$^*$-continuous completely positive complete contractions). We define the notion of approximately unital operator systems, and verify that operator systems considered in \cite{CvS} and \cite{CvS2} are approximately unital. If $S$ is approximately unital, then $ι_{S^*}:S^* \to S^\rd$ is an operator space isomorphism and $β_S: (S^\rd)^\rd\to S^{**}$ is a complete isometry. We will also establish that the restriction of the faithful functor $(S,T,φ)\mapsto (T^\rd, S^\rd, φ^\rd)$ to the category of approximately unital complete operator systems is both full and injective on objects.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05724
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Duality for operator systems with generating cones
Jia, Yu-Shu
Ng, Chi-Keung
Operator Algebras
Functional Analysis
Let $S$ be a complete operator system with a generating cone; i.e. $S_\sa = S_+ - S_+$. We show that there is a matrix norm on the dual space $S^*$, under which, and the usual dual matrix cone, $S^*$ becomes a dual operator system with a generating cone, denoted by $S^\rd$. The canonical complete order isomorphism $ι_{S^*}: S^* \to S^\rd$ is a dual Banach space isomorphism. Furthermore, we construct a canonical completely contractive weak$^*$-homeomorphism $β_S: (S^\rd)^\rd\to S^{**}$, and verify that it is a complete order isomorphism. For a complete operator system $T$ with a generating cone and a completely positive complete contraction $φ:S\to T$, there is a weak$^*$-continuous completely positive complete contraction $φ^\rd:T^\rd \to S^\rd$ with $ι_{S^*}\circ φ^* = φ^\rd \circ ι_{T^*}$. This produces a faithful functor from the category of complete operator systems with generating cones (where morphisms are completely positive complete contractions) to the category of dual operator systems with generating cones (where morphisms are weak$^*$-continuous completely positive complete contractions). We define the notion of approximately unital operator systems, and verify that operator systems considered in \cite{CvS} and \cite{CvS2} are approximately unital. If $S$ is approximately unital, then $ι_{S^*}:S^* \to S^\rd$ is an operator space isomorphism and $β_S: (S^\rd)^\rd\to S^{**}$ is a complete isometry. We will also establish that the restriction of the faithful functor $(S,T,φ)\mapsto (T^\rd, S^\rd, φ^\rd)$ to the category of approximately unital complete operator systems is both full and injective on objects.
title Duality for operator systems with generating cones
topic Operator Algebras
Functional Analysis
url https://arxiv.org/abs/2504.05724