2007/5/31, Antoni Mylka <<a href="mailto:antoni.mylka@dfki.uni-kl.de">antoni.mylka@dfki.uni-kl.de</a>>:<div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> <SNIP> I think It would be easier to reach an agreement if the solution would allow for different levels of detail, both during the creation of knowledge and during understanding. RDF has been created exactly for this purpose.</blockquote><div> I think this might be a good idea. So we have Xesam Core- and Xesam Extended ontologies. Here's a brain dump for what it's worth.... The core ontology would not have a concept of Categories - in the sense that categories defines a set of fields to expect on the object. Any old object only has a core set of fields defined. These could be (all in xesam namesapced):  * contributor (DC)  * creator (DC)  * description (DC)  * language (DC)  * publisher (DC)  * subject (DC)  * title (DC)  * license (an extensible vocabulary with predefined values GPL, LPGL, MIT etc)  * uri  * category (a controled vocabulary that maps to the cats in the extended onto)  * mime </div> * creationDate  * modificationDate With this simple onto you can actually do quite a bit of nifty stuff. With this in place it might also be easier to agree on extended ontology as Antoni already suggested. Cheers, Mikkel </div>