Added a section to my Sudoku Lens on Squidoo. This links to articles on the Math of Sudoku. Here’s the introduction I wrote:

No arithmetic is required to solve Sudoku. You don't add or multiple the numbers. In fact the numbers could just as well be hamsters or any other nine symbols.

The logic of Sudoku is mathematics. For example, there are computer programs to solve and to create Sudoku. So it is now the subject of a large number of papers. This is not the definitive list but a place to start if you want to explore Sudoku in more depth.