Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9497187 | Journal of Pure and Applied Algebra | 2005 | 27 Pages |
Abstract
The key part of the definition of a Hopf-Galois extension BâA over the Hopf algebra H is bijectivity of a canonical map β:AâBAâAâH. We develop criteria under which surjectivity of β (which is usually much easier to verify) is sufficient, and we investigate the consequences for the structure of A as a B-module and H-comodule. In particular, we prove equivariant projectivity of extensions in several important cases. We study these questions for generalizations of H-Galois extensions like Q-Galois extensions for a quotient coalgebra and one-sided module of a Hopf algebra H, and coalgebra Galois extensions.
Related Topics
Physical Sciences and Engineering
Mathematics
Algebra and Number Theory
Authors
Peter Schauenburg, Hans-Jürgen Schneider,