Twistings, crossed coproducts and Hopf-Galois coextensions

Caenepeel, S.; Wang, Dingguo; Wang, Yanxin

Twistings, crossed coproducts and Hopf-Galois coextensions

Authors

Caenepeel, S.

Wang, Dingguo

Wang, Yanxin

Description

Let $H$ be a Hopf algebra. Ju and Cai introduced the notion of twisting of an $H$-module coalgebra. In this note, we study the relationship between twistings, crossed coproducts and Hopf-Galois coextensions. In particular, we show that a twisting of an $H$-Galois coextension remains $H$-Galois if the twisting is invertible.
20 pages