by Brzeziński, Tomasz

Given a ring A and an A-coring C, we study when the forgetful functor from the category of right C-comodules to the category of right A-modules and its right adjoint −⊗
_A

C are separable. We then proceed to study when the induction functor −⊗
_A

C is also the left adjoint of the forgetful functor. This question is closely related to the problem when A→
_A
Hom(C,A) is a Frobenius extension. We introduce the notion of a Galois coring and analyse when the tensor functor over the subring of A fixed under the coaction of C is an equivalence. We also comment on possible dualisation of the notion of a coring.

DOI: 10.1023/A:1020139620841
Print publication date: 10/1/2002
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