Projectivity and flatness over the graded ring of semi-coinvariants

• Date: 2018
• Main Author: Guedenon, T.
• Format: Article
• Language: English
• Published: Lugansk National Taras Shevchenko University 2018
• Online Access: https://admjournal.luguniv.edu.ua/index.php/adm/article/view/640
• Journal Title: Algebra and Discrete Mathematics

Let \(k\) be a field, \(C\) a bialgebra with bijective antipode, \(A\) a right \(C\)-comodule algebra, \(G\) any subgroup of the monoid of grouplike elements of \(C\). We give necessary and sufficient conditions for the projectivity and flatness over the graded ring of semi-coinvariants of \(A\). Wh...