More on the Schur group of a commutative ring.
Natural endomorphisms of quasi-shuffle Hopf algebras
The Hopf algebra of word-quasi-symmetric functions (), a noncommutative generalization of the Hopf algebra of quasi-symmetric functions, can be endowed with an internal product that has several compatibility properties with the other operations on . This extends constructions familiar and central in the theory of free Lie algebras, noncommutative symmetric functions and their various applications fields, and allows to interpret as a convolution algebra of linear endomorphisms of quasi-shuffle...
Non-commutative separability and group actions.
We give conditions for the skew group ring S * G to be strongly separable and H-separable over the ring S. In particular we show that the H-separability is equivalent to S being central Galois extension. We also look into the H-separability of the ring S over the fixed subring R under a faithful action of a group G. We show that such a chain: S * G H-separable over S and S H-separable over R cannot occur, and that the centralizer of R in S is an Azumaya algebra in the presence of a central element...
Nonlinearity of the automorphism groups of some free algebras.
Notes on Galois extensions with inner Galois groups.
O automorfismech definovaných na okruhu endomorfismů homogenního totálně rozložitelného modulu
On a certain functional identity in prime rings. II.
On a class of free Galois extensions.
On a problem of commutativity of automorphisms.
On a theorem of P. E. Schupp. (Sur un théorème de P. E. Schupp.)
On abelian separable extensions and Galois sets of rings
On automorphism group of free quadratic extensions over a ring.
On automorphisms of quaternion orders.
On automorphisms of Weyl algebra
On Azumaya algebras with a finite automorphism group.
On Azumaya Galois extensions and skew group rings.
On central commutator Galois extensions of rings.
On centralizers of semiprime rings
Let be a semiprime ring and an additive mapping such that holds for all . Then is a left centralizer of . It is also proved that Jordan centralizers and centralizers of coincide.
On certain classes of Galois extensions of rings.
On characterizations of a center Galois extension.