Let k be a field and H a Hopf algebra over k with a bijective antipode. Suppose that H acts
on an associative (left noetherian) k-algebra R such that R is an H-module algebra. We …

Let H be a Hopf algebra over a field k, and A an H-comodule algebra. The categories of
comodules and relative Hopf modules are then Grothendieck categories with enough …

Let H be a Hopf algebra. We consider H-equivariant modules over a Hopf module category
C as modules over the smash extension CH. We construct Grothendieck spectral sequences …

We study certain comodule structures on spaces of linear morphisms between H-
comodules, where H is a Hopf algebra over the field k. We apply the results to show that H …

Given a Hopf algebra A, there exist various cohomology theories for the category of Hopf
bimodules over A, introduced by Gerstenhaber and Schack, and by Ospel. We prove, when …

Let W be a finite dimensional algebraic structure (eg an algebra) over a field K of
characteristic zero. We study forms of W by using Deligne's Theory of symmetric monoidal …

Given a Hopf algebra A, there exist various cohomology theories for the category of Hopf
bimodules over A, introduced by M. Gerstenhaber and SD Schack, and by C. Ospel. We …

Let C be a small category and ka field. There are two interesting mathematical subjects: the
category algebra kC and the classifying space| C|= BC. We study the ring homomorphism …

The category of graded, bicommutative Hopf algebras over the prime field with p elements is
an abelian category which is equivalent, by work of Schoeller, to a category of graded …

Let H be a Hopf algebra over a field k. We study O (H), the subalgebra of invariants of H
under the adjoint coaction, and prove that it is closely related to questions about the …