For a given entwining structure (A, C) ψinvolving an algebraA, a coalgebraC, and an
entwining map ψ: C⊗ A→ A⊗ C, a categoryMCA (ψ) of right (A, C) ψ-modules is defined and …

The notion of a coalgebra-Galois extension is defined as a natural generalisation of a Hopf-
Galois extension. It is shown that any coalgebra-Galois extension induces a unique …

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 …

Generalizing the notion of Galois corings, Galois comodules were introduced as comodules
P over an A-coring 𝒞 for which PA is finitely generated and projective and the evaluation …

The key part of the definition of a Hopf-Galois extension B⊂ A over the Hopf algebra H is
bijectivity of a canonical map β: A⊗ BA→ A⊗ H. We develop criteria under which surjectivity …

Genaralization fo cleft comodule algabras Page 1 COMMUNICATIONS IN ALGEBRA, 20(12),
3703-3721 (1992) GENERALIZATION OF CLEFT COMODULE ALGEBRAS Akira Masuoka …

The theory of general Galois-type extensions is presented, including the interrelations
between coalgebra extensions and algebra (co) extensions, properties of corresponding …

The theory of comodule algebras is a new subject with roots in the Hopf Galois theory of non-
sommutative rings and in the invariant theory of affine algebraic groups (cf.[4] and [7]). The …

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 …

This paper continues part of the investigation begun in [3], henceforth referred to as HLS,
into the structure of the algebras arising from the relaxation of the 2-cocycle condition of …