How to implement RELAX NG validation

I have written a paper describing one possible algorithm for implementing
RELAX NG validation.  This is the algorithm used by Jing, which I believe
has also been adopted by MSV.  See

  http://www.thaiopensource.com/relaxng/derivative.html

If you try to use this to implement RELAX NG and something isn't clear, let
me know and I'll try to improve the description.

James