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Projectivity of a relative Hopf module over the subring of coinvariants

S. Caenepeel·T. Guédeénon
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Abstract

Let $k$ be a commutative ring, $H$ a faithfully flat Hopf algebra with bijective antipode, $A$ a $k$-flat right $H$-comodule algebra. We investigate when a relative Hopf module is projective over the subring of coinvariants $B=A^{{\rm co}H}$, and we study the semisimplicity of the category of relative Hopf modules.

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S. Caenepeel, T. Guédeénon. 2002-10-18. Projectivity of a relative Hopf module over the subring of coinvariants. https://arxiv.org/abs/math/0210288

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