G-algebras, Jacobson radical and almost split sequences.
Galois actions on rings and finite Galois coverings.
Galois coverings and splitting properties of the ideal generated by halflines
Given a locally bounded k-category R and a group acting freely on R we study the properties of the ideal generated by a class of indecomposable locally finite-dimensional modules called halflines (Theorem 3.3). They are applied to prove that under certain circumstances the Galois covering reduction to stabilizers, for the Galois covering F: R → R/G, is strictly full (Theorems 1.5 and 4.2).
Galois coverings and the Clebsch-Gordan problem for quiver representations
We study the Clebsch-Gordan problem for quiver representations, i.e. the problem of decomposing the point-wise tensor product of any two representations of a quiver into its indecomposable direct summands. For this purpose we develop results describing the behaviour of the point-wise tensor product under Galois coverings. These are applied to solve the Clebsch-Gordan problem for the double loop quivers with relations αβ = βα = αⁿ = βⁿ = 0. These quivers were originally studied by I. M. Gelfand and...
Galois coverings and the problem of axiomatization of the representation type of algebras.
Galois coverings, Morita equivalence and smash extensions of categories over a field.
Galois coverings of representation-infinite algebras.
Galois extensions as functors of comodules.
Galois generators and the subspace theorem.
Galois H-objects with a normal basis in closed categories. A cohomological interpretation.
In this paper, for a cocommutative Hopf algebra H in a symmetric closed category C with basic object K, we get an isomorphism between the group of isomorphism classes of Galois H-objects with a normal basis and the second cohomology group H2(H,K) of H with coefficients in K. Using this result, we obtain a direct sum decomposition for the Brauer group of H-module Azumaya monoids with inner action:BMinn(C,H) ≅ B(C) ⊕ H2(H,K)In particular, if C is the symmetric closed category of C-modules with K a...
Galois modules and embedding problems.
Galoistheorien für Schiefkörper.
Gaussian and Prüfer conditions in bi-amalgamated algebras
Let and be two ring homomorphisms and let and be ideals of and , respectively, such that . In this paper, we investigate the transfer of the notions of Gaussian and Prüfer rings to the bi-amalgamation of with along with respect to (denoted by introduced and studied by S. Kabbaj, K. Louartiti and M. Tamekkante in 2013. Our results recover well known results on amalgamations in C. A. Finocchiaro (2014) and generate new original examples of rings possessing these properties.
Gelfand-Kirillor Dimension for non-Associative Algebras
Gel'fand-Kirillov dimension for algebras associated with the Weyl algebra
Gelfand-Kirillov dimension in some crossed products.
Gelfand-Kirillov Dimensions of a Tensor Product.
General sheaves over weighted projective lines
We develop a theory of general sheaves over weighted projective lines. We define and study a canonical decomposition, analogous to Kac's canonical decomposition for representations of quivers, study subsheaves of a general sheaf, general ranks of morphisms, and prove analogues of Schofield's results on general representations of quivers. Using these, we give a recursive algorithm for computing properties of general sheaves. Many of our results are proved in a more abstract setting, involving a hereditary...
Generalization of a theorem of Siegel
Generalizations of coatomic modules
For a ring R and a right R-module M, a submodule N of M is said to be δ-small in M if, whenever N+X=M with M/X singular, we have X=M. Let ℘ be the class of all singular simple modules. Then δ(M)=Σ{ L≤ M| L is a δ-small submodule of M} = Re jm(℘)=∩{ N⊂ M: M/N∈℘. We call M δ-coatomic module whenever N≤ M and M/N=δ(M/N) then M/N=0. And R is called right (left) δ-coatomic ring if the right (left) R-module R R(RR) is δ-coatomic. In this note, we study δ-coatomic modules and ring. We prove M=⊕i=1n Mi...