Radford's Formula for Bifrobenius Algebras and Applications |
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Authors: | Walter Ferrer Santos Mariana Haim |
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Affiliation: | 1. Faculty of Science , University of the Republic , Montevideo, Uruguay wrferrer@cmat.edu.uy;3. Faculty of Science , University of the Republic , Montevideo, Uruguay |
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Abstract: | In a biFrobenius algebra H, in particular in the case that H is a finite dimensional Hopf algebra, the antipode 𝒮:H → H can be decomposed as 𝒮 = tc ○ cφ where cφ:H → H* and tc:H* → H are the Frobenius and coFrobenius isomorphisms. We use this decomposition to present an easy proof of Radford's formula for 𝒮4. Then, in the case that the map 𝒮 satisfies the additional condition that 𝒮 id = id 𝒮 = u ?, we prove the trace formula tr(𝒮2) = ?(t)φ(1). We finish by applying the above results to study the semisimplicity and cosemisimplicity of H. |
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Keywords: | Antipode BiFrobenius algebra CoFrobenius isomorphism Cointegral Frobenius isomorphism Integral Radford's formula |
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