Algebras graded by discrete Doi-Hopf data and the Drinfeld double of a Hopf group-coalgebra

D. Bulacu, S. Caenepeel

We study Doi-Hopf data and Doi-Hopf modules for Hopf group-coalgebras. We introduce modules graded by a discrete Doi-Hopf datum; to a Doi-Hopf datum over a Hopf group coalgebra, we…