Extension to DocBook XML for using MathML markup

 The DocBook MathML module adds support for including MathML
 markup in DocBook XML source documents.
 .
 The MathML module is a customization of the full DocBook
 XML V4.1.2 DTD. The module requires access to the MathML V2.0 DTD
 provided by the w3-dtd-mathml package.