Products of C*-algebras that do not embed into the Calkin algebra

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Autori principali: Głodkowski, Damian, Koszmider, Piotr
Natura: Preprint
Pubblicazione: 2024
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author Głodkowski, Damian
Koszmider, Piotr
author_facet Głodkowski, Damian
Koszmider, Piotr
contents We consider the Calkin algebra $\mathcal{Q}(\ell_2)$, i.e., the quotient of the algebra $\mathcal B(\ell_2)$ of all bounded linear operators on the separable Hilbert space $\ell_2$ divided by the ideal $\mathcal K(\ell_2)$ of all compact operators on $\ell_2$. We show that in the Cohen model of set theory ZFC there is no embedding of the product $(c_0(2^ω))^{\mathbb{N}}$ of infinitely many copies of the abelian C*-algebra $c_0(2^ω)$ into $\mathcal{Q}(\ell_2)$ (while $c_0(2^ω)$ always embeds into $\mathcal{Q}(\ell_2)$). This enlarges the collection of the known examples due to Vaccaro and to McKenney and Vignati of abelian algebras, asymptotic sequence algebras, reduced products and coronas of stabilizations which consistently do not embed into the Calkin algebra. As in the Cohen model the rigidity of quotient structures fails in general, our methods do not rely on these rigidity phenomena as is the case of most examples mentioned above. The results should be considered in the context of the result of Farah, Hirshberg and Vignati which says that consistently all C*-algebras of density up to $2^ω$ do embed into $\mathcal{Q}(\ell_2)$. In particular, the algebra $(c_0(2^ω))^{\mathbb{N}}$ consistently embeds into the Calkin algebra as well.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11191
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Products of C*-algebras that do not embed into the Calkin algebra
Głodkowski, Damian
Koszmider, Piotr
Operator Algebras
Functional Analysis
Logic
We consider the Calkin algebra $\mathcal{Q}(\ell_2)$, i.e., the quotient of the algebra $\mathcal B(\ell_2)$ of all bounded linear operators on the separable Hilbert space $\ell_2$ divided by the ideal $\mathcal K(\ell_2)$ of all compact operators on $\ell_2$. We show that in the Cohen model of set theory ZFC there is no embedding of the product $(c_0(2^ω))^{\mathbb{N}}$ of infinitely many copies of the abelian C*-algebra $c_0(2^ω)$ into $\mathcal{Q}(\ell_2)$ (while $c_0(2^ω)$ always embeds into $\mathcal{Q}(\ell_2)$). This enlarges the collection of the known examples due to Vaccaro and to McKenney and Vignati of abelian algebras, asymptotic sequence algebras, reduced products and coronas of stabilizations which consistently do not embed into the Calkin algebra. As in the Cohen model the rigidity of quotient structures fails in general, our methods do not rely on these rigidity phenomena as is the case of most examples mentioned above. The results should be considered in the context of the result of Farah, Hirshberg and Vignati which says that consistently all C*-algebras of density up to $2^ω$ do embed into $\mathcal{Q}(\ell_2)$. In particular, the algebra $(c_0(2^ω))^{\mathbb{N}}$ consistently embeds into the Calkin algebra as well.
title Products of C*-algebras that do not embed into the Calkin algebra
topic Operator Algebras
Functional Analysis
Logic
url https://arxiv.org/abs/2412.11191