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A Note on the Antipode for Algebraic Quantum Groups

Published online by Cambridge University Press:  20 November 2018

L. Delvaux
Affiliation:
Department of Mathematics, University of Hasselt, Agoralaan, B-3590 Diepenbeek, Belgiume-mail: [email protected]
A. Van Daele
Affiliation:
Department of Mathematics, K.U. Leuven, Celestijnenlaan 200B, B-3001 Heverlee, Belgiume-mail: [email protected]
Shuanhong Wang
Affiliation:
Department of Mathematics, Southeast University, Nanjing 210096, Chinae-mail: [email protected]
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Abstract

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Recently, Beattie, Bulacu ,and Torrecillas proved Radford's formula for the fourth power of the antipode for a co-Frobenius Hopf algebra.

In this note, we show that this formula can be proved for any regular multiplier Hopf algebra with integrals (algebraic quantum groups). This, of course, not only includes the case of a finite-dimensional Hopf algebra, but also that of any Hopf algebra with integrals (co-Frobenius Hopf algebras). Moreover, it turns out that the proof in this more general situation, in fact, follows in a few lines from well-known formulas obtained earlier in the theory of regular multiplier Hopf algebras with integrals.

We discuss these formulas and their importance in this theory. We also mention their generalizations, in particular to the (in a certain sense) more general theory of locally compact quantum groups. Doing so, and also because the proof of the main result itself is very short, the present note becomes largely of an expository nature.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2012

References

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