Monoidal Categories of Comodules for Coquasi Hopf Algebras and Radford’s Formula
نویسندگان
چکیده
We study the basic monoidal properties of the category of Hopf modules for a coquasi Hopf algebra. In particular we discuss the so called fundamental theorem that establishes a monoidal equivalence between the category of comodules and the category of Hopf modules. We present a categorical proof of Radford’s S formula for the case of a finite dimensional coquasi Hopf algebra, by establishing a monoidal isomorphism between certain double dual functors. Dedicated to I. Shestakov on the occasion of his 60th birthday
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