Given a finite automorphism group G of a field extension E⊃ K, E can be considered as
module over the group algebra K [G]. Moreover, E can also be viewed as a comodule over …

Introduction. Let R be a commutative ring with identity, H a finite co-commutative Hopf
algebra over R and A an//-Hopf Galois extension of R in the sense of [15]. When R is a field …

Let H be a Hopf algebra over the field k and B⊂ A a right faithfully flat right H-Galois
extension. The aim of this paper is to study some questions of representation theory …

Galois comodules of a coring are studied. The conditions for a simple comodule to be a
Galois comodule are found. A special class of Galois comodules termed principal …

Let k be a commutative base ring and H a Hopf algebra. An H-Galois extension A of k is an
H-comodule algebra such that A'"= k and a certain map A@ A+ A@ H is bijective. The notion …

For a long period the theory of modules over rings on the one hand and comodules and
Hopf modules for coalgebras and bialgebras on the other side developed quite …

Corings can be viewed as coalgebras over noncommutative rings, in fact they are
coalgebras in the monoidal category of bimodules over a (noncommutative) ring. A beautiful …

Galois extensions as functors of comodules Page 1 manuscripta math. 59, 391 397 (1987)
manuscripta mathemati ca @ Springcr-Verlag 1987 GALOIS EXTENSIONS AS FUNCTORS OF …

We work over a fixed ground field k in arbitrary characteristic. Let R be a prime algebra, and
let Q denote the symmetric Martindale quotient ring of R. We know from [10, Section 6.4] that …

Hopf-Galois extensions were introduced by Chase and Sweedler [8](in the commutative
case) and Kreimer and Takeuchi [25](in the case of finite dimensional Hopf algebras) by …