+------------------------+
                         |   Gump Metadata DTDs   |
                         +------------------------+
            
This is the collection of DTDs used by Gump to validate its metadata.

These DTD are, admittedly, pretty lousy ones, but they are better than nothing.

The semantic structure of the Gump metadata descriptors make it impossible
to write a seriously validating DTD because there are times where the 
requirement of a particular attribute depend on the existance of a nested
element. 

This is something that DTDs (and XMLSchemas for that matter)
don't have a way to indicate. This is the reason why pretty much all
attributes are optional and the "location" and "enumeration" of the 
elements are not fixed. 

Admittedly, this ends up in a much less validating
DTD but I [SM] personally believe it would cause more pain than value to
make the format any more strict at this time.

I [SM] would also add that how the use of RDF (especially in its N3 syntax 
definition) would make all the above problems (induced by the abuse of the 
XML model that really does not fit the description of semi-structured relational
metadata) go away.