Error in RelaxNG schema

Hello,

The MathML RelaxNG schema does not allow a negative /rownumber/ for the 
align attribute of mtable. A minus sign should be added to the pattern.

mtable.attributes =
   CommonAtt, CommonPresAtt,
   attribute align {xsd:string {
     pattern ='\s*(top|bottom|center|baseline|axis)\s*[0-9]*'}}?,

(discovered by trying to validate 
http://www.mozilla.org/projects/mathml/demo/mtable.html with 
http://validator.w3.org/nu/)

-- 
Frédéric Wang
maths-informatique-jeux.com/blog/frederic