Projectivity and flatness over the graded ring of semi-coinvariants

• Published in: Algebra and Discrete Mathematics
• Date: 2010
• Main Author: Guedenon, T.
• Format: Article
• Language: English
• Published: Інститут прикладної математики і механіки НАН України 2010
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/154619
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Projectivity and flatness over the graded ring of semi-coinvariants / T. Guedenon // Algebra and Discrete Mathematics. — 2010. — Vol. 10, № 1. — С. 43–56. — Бібліогр.: 13 назв. — англ.

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. When A and C are commutative a...