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From Quantum Groups to Groups

Published online by Cambridge University Press:  20 November 2018

Mehrdad Kalantar
Affiliation:
School of Mathematics and Statistics, Carleton University, Ottawa, Ontario K1S 5B6, e-mail: [email protected]
Matthias Neufang
Affiliation:
School of Mathematics and Statistics, Carleton University, Ottawa, Ontario, K1S 5B6, e-mail: [email protected]
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Abstract

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In this paper we use the recent developments in the representation theory of locally compact quantum groups, to assign to each locally compact quantum group $\mathbb{G}$ a locally compact group $\tilde{\mathbb{G}}$ that is the quantum version of point-masses and is an invariant for the latter. We show that “quantum point-masses” can be identified with several other locally compact groups that can be naturally assigned to the quantum group $\mathbb{G}$. This assignment preserves compactness as well as discreteness (hence also finiteness), and for large classes of quantum groups, amenability. We calculate this invariant for some of the most well-known examples of non-classical quantum groups. Also, we show that several structural properties of $\mathbb{G}$ are encoded by $\tilde{\mathbb{G}}$ the latter, despite being a simpler object, can carry very important information about $\mathbb{G}$.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2013

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