looked Xdelta (http://www.bath.ac.uk/~ccslrd/delta/index.html) , a direct translation of Delta format in XML; comments: probably better to declare character numbers as ID; characters could be turned into rdf:Property

<offtopic> Character numbers can't be declared as ID if you want to use numbers. The value of ID attributes has to match the Name production in the XML spec. Take the following document: <!DOCTYPE bar [ <!ELEMENT bar EMPTY> <!ATTLIST bar attrib ID #REQUIRED> ]> <bar attrib="1" /> Run it through RXP: C:\temp>e:\rxp\rxp -xVS bar.xml Warning: The attribute attrib of element bar is declared as ID but contains a token that does not start with a name character in unnamed entity at line 5 char 16 of file:/C:/temp/bar.xml <bar attrib="1"></bar> Besides IDs are fairly useless, Schema based validation will likely hold more value. </offtopic> I'm hoping at some point to revisit XDELTA, to take a step back and apply some comments/requirements that have surfaced on this list. If nothing else it might be a talking point. I'll ditch traditional DTDs and use a Schema based validation mechanism instead. Cheers, L.