Characteristic properties of corings with a grouplike element are analysed. Associated differential graded rings are studied. A correspondence between categories of comodules and flat connections is established. A generalisation of the Cuntz-Quillen theorem relating existence of connections in a module to projectivity of this module is proven.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-bc61-0-2, author = {Tomasz Brzezi\'nski}, title = {The structure of corings with a grouplike element}, journal = {Banach Center Publications}, volume = {60}, year = {2003}, pages = {21-35}, zbl = {1066.16034}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc61-0-2} }
Tomasz Brzeziński. The structure of corings with a grouplike element. Banach Center Publications, Tome 60 (2003) pp. 21-35. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc61-0-2/