Alex Brown wrote: > I'm sure I don't know anything about the maths of all this, Welcome to the club ;-)
I agree with everything you say, except that in SMW "is a" is the semantically correct thing to use Category for (if you care about semantic correctness). > but isn't > the obvious solution to have SMW use *something else* to represent > it's isa relationship (e.g. [[Isa::Thing]], No, "is a" maps pretty well to rdf:type. From http://www.w3.org/TR/rdf-schema/#ch_type , "rdf:type is an instance of rdf:Property that is used to state that a resource is an instance of a class." So putting [[Category:Cities]] in the San Diego article makes sense, because San Diego is a city and in RDF Export this becomes rdf:type Category-3ACities. The problem (if you care about semantic correctness) comes when people use categories for articles that aren't simple "is a", like "Suburb", "Urban Culture", etc. That's when you need something instead of the Category property, e.g. Yaron Koren suggested [[Relation:Covers Topic]]. It's an interesting question whether the object of such a relation should be a MediaWiki category. Interestingly, Wikipedia editors have noticed this confusion. As http://en.wikipedia.org/wiki/Category:City says This category contains articles on the study of cities. For articles on cities themselves, see Category:Cities. That's somewhat ad hoc, and maybe something more explicit like "Category:City (topic)" is better, but it shows the wisdom of crowds. (ontoworld.org users tend to create singular category names, but English Wikipedia is pretty consistent about using plural for classes of things.) From my reading of http://www.w3.org/TR/swbp-skos-core-guide/ , it seems it can identify knowledge organization schemes like classifications, taxonomies, subject headings. So you can put lots of SKOS relations in your Category and topic pages to formalize their organization. And then I believe [[Relation:Covers Topic]] should be exported in RDF as skos:subject. (There's also Dublin Core metadata's dc:subject, it's looser.) I think other problematic uses of Category can be addressed a similar way. I created http://ontoworld.org/wiki/Category:Knowledge_organization if people want to try "fixing" categories. It would be nice if ontoworld.org imported RDFS, Dublin Core, and SKOS vocabularies (see http://ontoworld.org/wiki/Help:Import_vocabulary). Then people could play around with associating SMW relations with terms from these vocabularies and see what happens in RDF Export. I don't have admin rights to set up http://ontoworld.org/wiki/MediaWiki:Smw_import_skos, etc. Respectfully yours, -- =S Page ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Semediawiki-user mailing list Semediawiki-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/semediawiki-user
