On Wed, May 28, 2014 at 2:48 PM, Markus Krötzsch <mar...@semantic-mediawiki.org> wrote: > David, > > Regarding the question of how to classify properties and how to relate them > to items: > > * "same as" (in the sense of owl:sameAs) is not the right concept here. In > fact, it has often been discouraged to use this on the Web, since it has > very strong implications: it means that in all uses of the one identifier, > one could just as well use the other identifier, and that it is > indistinguishable if something has been said about the one or the other. > That seems too strong here, at least for most cases. > > * In the world of OWL DL, sameAs specifically refers to individuals, not to > classes or properties. Saying "P sameAs Q" does not imply that P and Q have > the same extension as properties. For the latter, OWL has the relationship > owl:equivalentProperties. This distinction of instance level and schema > level is similar to the distinction we have between "instance of" and > "subclass of". > > * Therefore, I would suggest to use a property called "subproperty of" as > one way of relating properties (analogously to "subclass of"). It has to be > checked if this actually occurs in Wikidata (do we have any properties that > would be in this relation, or do we make it a modelling principle to have > only the most specific properties in Wikidata?). > > * The relationship from properties to items could be modelled with the > existing property "subject of" (P805). > > * It might be useful to also have a taxonomic classification of properties. > For example, we already group properties into properties for "people", > "organisations", etc. Such information could also be added with a specific > property (this would be a bit more like a "category" system on property > pages).
Yes. That's the way forward for now. > On the other hand, some of this might coincide with constraint > information that could be expressed as claims. For instance, person > properties might be those with "Type" (i.e., "rdfs:domain") constraint > human. By the way, our constraint system could use some systematisation -- > there are many overlaps in what you can do with one constraint or another. I hope to have a team of students work on improving constraints reports and everything around it later in the year. It'll depend on if they pick this project though. Cheers Lydia -- Lydia Pintscher - http://about.me/lydia.pintscher Product Manager for Wikidata Wikimedia Deutschland e.V. Tempelhofer Ufer 23-24 10963 Berlin www.wikimedia.de Wikimedia Deutschland - Gesellschaft zur Förderung Freien Wissens e. V. Eingetragen im Vereinsregister des Amtsgerichts Berlin-Charlottenburg unter der Nummer 23855 Nz. Als gemeinnützig anerkannt durch das Finanzamt für Körperschaften I Berlin, Steuernummer 27/681/51985. _______________________________________________ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
