Non-Commutative Algebra and Geometry (Fall 2002)

Course Description. The official course description is a reasonably honest account of what we will do, but my motivation for teaching this course is coming from string theory. I know essentially no physics. But recent string theory papers are filled with various non-commutative algebras that are ``old friends'' of mine. I would like to address some questions about these algebras that are of interest to string theorists. There is a language barrier unfortunately. All I know for sure is that the string theorists are interested in the finite-dimensional representations of (= modules over) these algebras. What these algebras have in common is that they are finite modules over their centers, and their centers correspond to interesting algebraic varieties; these varieties are usually singular and the string theorists are interested in the non-commutative algebras because they provide some sort of ``non-commutative resolutions'' of the varieties. The ``points'' on the non-commutative space are provided by the finite-dimensional simple modules over the non-commutative algebras. I am sure that some of you will know much more physics than I do. I will not attempt to explain any physics in this course, but here are some papers by string theorists in which you will find all sorts of interesting non-commutative algebras:

And here's a book: Physics in Noncommutative World: I Field Theories Ed by Miao Li and Yong-Shi Wu.

This course will cover some of the algebraic background needed to understand the algebras appearing in these string theory papers. There will be no physics in this course.


Course Notes. These are posted in three file formats: pdf, dvi, and postscript.

Chapter 1. Rings, Modules, and Algebras. This is background but worth reading anyway---think of it as a refresher course. And here are the dvi and ps files.

Chapter 2. Noncommutative Polynomial Equations. And here is the ps file.

Chapter 3. Prime ideals and Spec(A). And here is the ps file.

Chapter 4. Quick Homological Algebra. And here are the ps and dvi files.

Chapter 5. Artinian Rings. And here is the ps file.

Chapter 6. Representations of Quivers. And here is the ps file.

As you will have guessed, I have fallen way behind in posting course notes. I hope to catch up with what we have covered in class... and when I do I will post more course notes.


If you are following this course you might also be interested in visiting Lieven LeBruyn's noncommutative algebra & geometry pages, na&g, for short, and also his course page where you will find notes for some courses he is teaching.