Partially Positive Semidefinite Maps on $*$-Semigroupoids and Linearisations

Fuente: arXiv
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Autori principali: Gheondea, Aurelian, Udrea, Bogdan
Natura: Preprint
Pubblicazione: 2023
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author Gheondea, Aurelian
Udrea, Bogdan
author_facet Gheondea, Aurelian
Udrea, Bogdan
contents Motivated by Cuntz-Krieger-Toeplitz systems associated to undirected graphs and representations of groupoids, we obtain a generalisation of the Sz-Nagy's Dilation Theorem for operator valued partially positive semidefinite maps on $*$-semigroupoids with unit, with varying degrees of aggregation, firstly by $*$-representations with unbounded operators and then we characterise the existence of the corresponding $*$-representations by bounded operators. By linearisation of these constructions, we obtain similar results for operator valued partially positive semidefinite maps on $*$-algebroids with unit and then, for the special case of $B^*$-algebroids with unit, we obtain a generalisation of the Stinespring's Dilation Theorem. As an application of the generalisation of the Stinespring's Dilation Theorem, we show that some natural questions on $C^*$-algebroids are equivalent.
format Preprint
id arxiv_https___arxiv_org_abs_2302_13107
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Partially Positive Semidefinite Maps on $*$-Semigroupoids and Linearisations
Gheondea, Aurelian
Udrea, Bogdan
Operator Algebras
Primary 47L75, Secondary 43A35, 47A20, 47L60, 46L99
Motivated by Cuntz-Krieger-Toeplitz systems associated to undirected graphs and representations of groupoids, we obtain a generalisation of the Sz-Nagy's Dilation Theorem for operator valued partially positive semidefinite maps on $*$-semigroupoids with unit, with varying degrees of aggregation, firstly by $*$-representations with unbounded operators and then we characterise the existence of the corresponding $*$-representations by bounded operators. By linearisation of these constructions, we obtain similar results for operator valued partially positive semidefinite maps on $*$-algebroids with unit and then, for the special case of $B^*$-algebroids with unit, we obtain a generalisation of the Stinespring's Dilation Theorem. As an application of the generalisation of the Stinespring's Dilation Theorem, we show that some natural questions on $C^*$-algebroids are equivalent.
title Partially Positive Semidefinite Maps on $*$-Semigroupoids and Linearisations
topic Operator Algebras
Primary 47L75, Secondary 43A35, 47A20, 47L60, 46L99
url https://arxiv.org/abs/2302.13107