Freddy Van Oystaeyen

Methods of graded rings

The Category of Graded Rings.- The Category of Graded Modules.- Modules over Stronly Graded Rings.- Graded Clifford Theory.- Internal Homogenization.- External Homogenization.- Smash Products.- Localization of Graded Rings.- Application to Gradability.- Appendix A: Some Category Theory.- Appendix B: Dimensions in an Abelian Category.- Bibliography.- Index.

Dimensions of ring theory

1. Finiteness Conditions for Lattices.- 1.1. Lattices.- 1.2. Noetherian and Artinian Lattices.- 1.3. Lattices of Finite Length.- 1.4. Irreducible Elements in a Lattice.- 1.5. Goldie Dimension of a Modular Lattice.- 1.6. Goldie Dimension and Chain Conditions for Modular Lattices with Finite Group Actions.- 1.7. Complements and Pseudo-Complements.- 1.8. Semiatomic Lattices and Compactly Generated Lattices.- 1.9. Semiartinian Lattices.- 1.10. Indecomposable Elements in a Lattice.- 1.11. Exercises.- Bibliographical Comments to Chapter 1.- 2. Finiteness Conditions for Modules.- 2.1. Modules.- 2.2. The Lattice of Submodules of a Module.- 2.3. Noetherian and Artinian Modules.- 2.4. Modules of Finite Length.- 2.5. Semisimple Modules.- 2.6. Semisimple and Simple Artinian Rings.- 2.7. The Jacobson Radical and the Prime Radical of a Ring.- 2.8. Rings of Fractions. Goldies Theorems.- 2.9. Artinian Modules which are Noetherian.- 2.10. Projective and Infective Modules.- 2.11. Tensor Product and Flat Modules.- 2.12. Normalizing Extensions of a Ring.- 2.13. Graded Rings and Modules.- 2.14. Graded Rings and Modules of Type ?. Internal Homogenisation.- 2.15. Noetherian Modules over Graded Rings of Type ?. Applications.- 2.16. Strongly Graded Rings and Clifford Systems for Finite Groups.- 2.17. Invariants of a Finite Group Action.- 2.18. Exercises.- Bibliographical Comments to Chapter 2.- 3. Krull Dimension and Gabriel Dimension of an Ordered Set.- 3.1. Definitions and Basic Properties.- 3.2. The Krull Dimension of a Modular Lattice.- 3.3. Critical Composition Series of a Lattice.- 3.4. The Gabriel Dimension of a Modular Lattice.- 3.5. Comparison of Krull and Gabriel Dimension.- 3.6. Exercises.- Bibliographical Comments to Chapter 3.- 4. Krull Dimension and Gabriel Dimension of Rings and Modules.- 4.1. Definitions and Generalities.- 4.2. Krull and Gabriel Dimension of Some Special Classes of Rings and Modules.- 4.2.1. The Ring of Endomorphisms of a Projective Finitely Generated Module.- 4.2.2. Normalizing Extensions.- 4.2.3. Rings Strongly Graded by a Finite Group.- 4.2.4. The Ring of Invariants.- 4.2.5. Graded Rings of Type ?.- 4.2.6. Filtered Rings and Modules.- 4.2.7. Ore and Skew-Laurent Extensions.- 4.2.8. Affine P.I. Algebras.(Addendum).- 4.3. Exercises.- Bibliographical Comments to Chapter 4.- 5. Rings with Krull Dimension.- 5.1. Nil Ideals.- 5.2. Semiprime Rings with Krull Dimension.- 5.3. Classical Krull Dimension of a Ring.- 5.4. Associated prime Ideals.- 5.5. Fully Left Bounded Rings with Krull Dimension.- 5.6. Examples of Noetherian Rings of Arbitrary Krull Dimension.- 5.7. Exercises.- Bibliographical Comments to Chapter 5.- 6. Krull Dimension of Noetherian Rings. The Principal Ideal Theorem.- 6.1. Fully Left Bounded Left Noetherian Rings.- 6.2. The Reduced Rank of a Module.- 6.3. Noetherian Rings Satisfying Condition H.- 6.4. Fully Bounded Noetherian Rings.- 6.5. Krull Dimension and Invertible Ideals in a Noetherian Ring.- 6.6. The Principal Ideal Theorem.- 6.7. Exercises.- Bibliographical Comments to Chapter 6.- 7. Relative Krull and Gabriel Dimensions.- 7.1. Additive Topologies and Torsion Theories.- 7.2. The Lattices CF (M) and CHg.- 7.3. Relative Krull Dimension.- 7.4. Relative Krull Dimension Applied to the Principal Ideal Theorem.- 7.5. Relative Gabriel Dimension.- 7.6. Relative Krull and Gabriel Dimensions of Graded Rings.- 7.7. Exercises.- Bibliographical Comments to Chapter 7.- 8. Homological Dimensions.- 8.1. The Projective Dimension of a Module.- 8.2. Homological Dimension of Polynomial Rings and Rings of Formal Power Series.- 8.3. Injective Dimension of a Module.- 8.4. The Flat Dimension of a Module.- 8.5. The Artin-Rees Property and Homological Dimensions.- 8.6. Regular Local Rings.- 8.7. Exercises.- Bibliographical Comments to Chapter 8.- 9. Rings of Finite Global Dimension.- 9.1. The Zariski Topology.- 9.2. The Local Study of Homological Dimension.- 9.3. Rings Integral over their Centres.- 9.4. Commutative Rings of Finite Global Dimension.- 9.5. Exercises.- Bibliographical Comments to Chapter 9.- 10. The Gelfand-Kirillov Dimension.- 10.1. Definitions and Basic Properties.- 10.2. GK-dimension of Filtered and Graded Algebras.- 10.3. Applications to Special Classes of Rings.- 10.3.1. Rings of Differential Operators and Weyl Algebras.- 10.3.2. Remarks on Enveloping Algebras of Lie Algebras.(Addendum)..- 10.3.3. P.I.Algebras.(Addendum).- 10.4. Exercises.- Bibliographical Comments to Chapter 10.- References.

General twisting of algebras

Abstract We introduce the concept of pseudotwistor (with particular cases called twistor and braided twistor) for an algebra ( A , μ , u ) in a monoidal category, as a morphism T : A ⊗ A → A ⊗ A satisfying a list of axioms ensuring that ( A , μ ○ T , u ) is also an algebra in the category. This concept provides a unifying framework for various deformed (or twisted) algebras from the literature, such as twisted tensor products of algebras, twisted bialgebras and algebras endowed with Fedosov products. Pseudotwistors appear also in other topics from the literature, e.g. Durdevichs braided quantum groups and ribbon algebras. We also focus on the effect of twistors on the universal first order differential calculus, as well as on lifting twistors to braided twistors on the algebra of universal differential forms.

The Green rings of Taft algebras

We compute the Green ring of the Taft algebra

Generalized Diagonal Crossed Products and Smash Products for Quasi-Hopf Algebras. Applications

H_n(q)

Saturated Kochen–Specker-type configuration of 120 projective lines in eight-dimensional space and its group of symmetry

, where

Some bialgebroids constructed by Kadison and Connes-Moscovici are isomorphic ∗

n

Discrete Valuations Extend to Certain Algebras of Quantum Type

is a positive integer greater than 1, and

Localization of fully left bounded rings

q

A structure theorem for quasi-Hopf comodule algebras

is an