Abstract
The notions of group coalgebra Galois extension and group entwining structure are defined. It is proved that any group coalgebra Galois extension induces a unique group-entwining map ψ = {ψα, β}α, β∈π compatible with the right group coaction, generalizing the recent work of Brzeziński and Hajac [Brzeziński, T., Hajac, P. M. (1999). Coalgebra extensions and algebra coextensions of Galois type. Comm. Algebra 27:1347–1368].
Acknowledgments
The author would like to thank the referee for his/her helpful comments on this paper. This work was supported in part by the Science Foundation of Henan Province for Distinguished Young Scholars and the NSF of China.
Notes
#Communicated by M. Cohen.