Projectivity and freeness over comodule algebras
نویسندگان
چکیده
منابع مشابه
Projectivity and freeness over comodule algebras
Let H be a Hopf algebra and A an H-simple right H-comodule algebra. It is shown that under certain hypotheses every (H,A)-Hopf module is either projective or free as an A-module and A is either a quasi-Frobenius or a semisimple ring. As an application it is proved that every weakly finite (in particular, every finite dimensional) Hopf algebra is free both as a left and a right module over its f...
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Let H be a Hopf algebra over a field k and A a right coideal subalgebra of H , that is, A is a subalgebra satisfying ∆(A) ⊂ A⊗H where ∆ is the comultiplication in H . In case when H is finitely generated commutative, the right coideal subalgebras are intimately related to the homogeneous spaces for the corresponding group scheme. The purpose of this paper is to extend the class of pairsA,H for ...
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ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 2007
ISSN: 0002-9947,1088-6850
DOI: 10.1090/s0002-9947-07-03979-7