Given a group π, we use involutory Hopf π-coalgebras to define a scalar invariant of flat π-bundles over 3-manifolds. When π = 1, this invariant equals the one for 3-manifolds constructed by Kuperberg from involutory Hopf algebras. We give examples which show that this invariant is non-trivial.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm188-0-11, author = {Alexis Virelizier}, title = {Involutory Hopf group-coalgebras and flat bundles over 3-manifolds}, journal = {Fundamenta Mathematicae}, volume = {185}, year = {2005}, pages = {241-270}, zbl = {1118.57017}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm188-0-11} }
Alexis Virelizier. Involutory Hopf group-coalgebras and flat bundles over 3-manifolds. Fundamenta Mathematicae, Tome 185 (2005) pp. 241-270. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm188-0-11/