Description
Quadratic algebras, i.e., algebras defined by quadratic relations, often occur in various areas of mathematics. One of the main problems in the study of these (and similarly defined) algebras is how to control their size. A central notion in solving this problem is the notion of a Koszul algebra, which was introduced in 1970 by S. Priddy and then appeared in many areas of mathematics, such as algebraic geometry, representation theory, noncommutative geometry, $K$-theory, number theory, and noncommutative linear algebra.
The book offers a coherent exposition of the theory of quadratic and Koszul algebras, including various definitions of Koszulness, duality theory, Poincaré-Birkhoff-Witt-type theorems for Koszul algebras, and the Koszul deformation principle. In the concluding chapter of the book, they explain a surprising connection between Koszul algebras and one-dependent discrete-time stochastic processes.
Chapter
0. Conventions and notation
2. Quadratic algebras and modules
5. Low-dimensional cohomology
6. Lattices and distributivity
7. Lattices of vector spaces
Chapter 2. Koszul algebras and modules
4. Distributivity and n-Koszulness
5. Homomorphisms of algebras and Koszulness. I
6. Homomorphisms of algebras and Koszulness. II
7. Koszul algebras in algebraic geometry
8. Infinitesimal Hopf algebra associated with a Koszul algebra
9. Koszul algebras and monoidal functors
10. Relative Koszulness of modules
Chapter 3. Operations on graded algebras and modules
1. Direct sums, free products and tensor products
2. Segre products and Veronese powers. I
3. Segre products and Veronese powers. II
4. Internal cohomomorphism
5. Koszulness cannot be checked using Hilbert series
Chapter 4. Poincaré–Birkhoff–Witt Bases
3. PBW-bases and Koszulness
4. PBW-bases and operations on quadratic algebras
5. PBW-bases and distributing bases
6. Hilbert series of PBW-algebras
7. Filtrations on quadratic algebras
11. Three-dimensional Sklyanin algebras
Chapter 5. Nonhomogeneous Quadratic Algebras
2. Nonhomogeneous PBW-theorem
3. Nonhomogeneous quadratic modules
4. Nonhomogeneous quadratic duality
6. Nonhomogeneous duality and cohomology
7. Bar construction for CDG- lgebras and modules
8. Homology of completed cobar-complexes
Chapter 6. Families of quadratic algebras and Hilbert series
1. Openness of distributivity
2. Deformations of Koszul algebras
3. Upper bound for the number of Koszul Hilbert series
4. Generic quadratic algebras
5. Examples with small dim A[sub(1)] and dim A[sub(2)]
6. Koszulness is not constructible
7. Families of quadratic algebras over schemes
Chapter 7. Hilbert series of Koszul algebras and one-dependent processes
1. Conjectures on Hilbert series of Koszul algebras
3. Koszul duality and inequalities
4. One-dependent processes
5. PBW-algebras and two-block-factor processes
6. Operations on one-dependent processes
7. Hilbert space representations of one-dependent processes
8. Hilbert series of one-dependent processes
9. Hermitian construction of one- ependent processes
10. Modules over one-dependent processes
Appendix A. DG-algebras and Massey products