Coalgebra Extensions and Algebra Coextensions of Galois Type
q-alg
2008-02-03 v2 Quantum Algebra
Rings and Algebras
Abstract
The notion of a coalgebra-Galois extension is defined as a natural generalisation of a Hopf-Galois extension. It is shown that any coalgebra-Galois extension induces a unique entwining map compatible with the right coaction. For the dual notion of an algebra-Galois coextension it is also proven that there always exists a unique entwining structure compatible with the right action.
Cite
@article{arxiv.q-alg/9708010,
title = {Coalgebra Extensions and Algebra Coextensions of Galois Type},
author = {Tomasz Brzezinski and Piotr M. Hajac},
journal= {arXiv preprint arXiv:q-alg/9708010},
year = {2008}
}
Comments
21 pages, LaTeX, uses amssymb. Major revision. Version to appear in Commun. Algebra