Dear Sir
 
 
Please find attached the "example.xml" made by docbook v5  namespaces and it didn't validated on XMLSpy or XMetal. When I add the Doctype declaration, namespaces didn't work. And I can't use Relax ng schema because not all XML editors, as menshioned before, understand this schema.   Could I extend the "equation" element definition in Doctype declaration, because I think it lakes "mml:math" in the content model of "equation" element.  Please help me and validate this file.
 
Best regards
 
Kader