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Proceedings of the American Mathematical Society
Proceedings of the American Mathematical Society
ISSN 1088-6826 (e) ISSN 0002-9939 (p)
     

When weak Hopf algebras are Frobenius

Author(s): Miodrag Cristian Iovanov; Lars Kadison
Journal: Proc. Amer. Math. Soc.
MSC (2000): Primary 18D10; Secondary 16W30, 16S50, 16D90, 16L30
Posted: October 22, 2009
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Abstract: We investigate when a weak Hopf algebra $ H$ is Frobenius. We show this is not always true, but it is true if the semisimple base algebra $ A$ has all its matrix blocks of the same dimension. However, if $ A$ is a semisimple algebra not having this property, there is a weak Hopf algebra $ H$ with base $ A$ which is not Frobenius (and consequently, it is not Frobenius ``over'' $ A$ either). Moreover, we give a categorical counterpart of the result that a Hopf algebra is a Frobenius algebra for a noncoassociative generalization of a weak Hopf algebra.


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Additional Information:

Miodrag Cristian Iovanov
Affiliation: Faculty of Mathematics, University of Bucharest, Str. Academiei 14, RO-70109, Bucharest, Romania - and - State University of New York, Buffalo, 244 Mathematics Building, Buffalo, New York 14260-2900
Email: yovanov@gmail.com, e-mail@yovanov.net

Lars Kadison
Affiliation: Department of Mathematics, University of Pennsylvania, David Rittenhouse Laboratory, 209 S. 33rd Street, Philadelphia, Pennsylvania 19104
Address at time of publication: Department of Mathematics, University of California at San Diego, 9500 Gilman Drive, \#0112, La Jolla, California 92093
Email: lkadison@math.upenn.edu

DOI: 10.1090/S0002-9939-09-10121-1
PII: S 0002-9939(09)10121-1
Keywords: Weak Hopf algebra, quasi-Hopf algebra, Frobenius algebra, quasi-Frobenius algebra, tensor category, Tannakian reconstruction
Received by editor(s): November 20, 2008,
Received by editor(s) in revised form: July 15, 2009
Posted: October 22, 2009
Additional Notes: The first author was partially supported by contract no. 24/28.09.07 with UEFISCU ``Groups, quantum groups, corings and representation theory'' of CNCIS, PN II (ID\_1002).
Communicated by: Martin Lorenz
Copyright of article: Copyright 2009, American Mathematical Society
The copyright for this article reverts to public domain after 28 years from publication.


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