Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
Hi James, My mistake, I should have linked to https://www.wikidata.org/wiki/Property_talk:P1647, which includes the following in the 'Examples' section of the documentation template: Note: it is not valid to declare subproperties of instance of (P31) (rdf:type), subclass of (P279) (rdfs:subClassOf) or any other property mapped to a built-in property of RDF, RDFS or OWL. See creation discussion. The creation discussion is available at https://www.wikidata.org/wiki/Wikidata:Property_proposal/Archive/27#subproperty_of . Eric ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
As someone relatively new to Wikidata, I need to ask for some help understanding the following paragraph from the forwarded email: Please note that *instance of* (P31) and *subclass of* (P279) are not valid values for *subproperty of* (P1647) claims, as described in the P1647 documentation [1]. For example, claims like occupation *subproperty of* instance of are invalid. What specifically in the P1647 documentation [1] describes that *instance of* (P31) and *subclass of* (P279) are not valid values for *subproperty of* (P1647) claims? [1]https://www.wikidata.org/wiki/Property:P1647 Thanks, James Weaver On Sat, Jan 10, 2015, at 02:25 PM, Emw wrote: Since it appears that the creation of *subproperty of* went unnoticed by many, I'd like to describe an important aspect of its proper use, and how that relates to classification. Please note that *instance of* (P31) and *subclass of* (P279) are not valid values for *subproperty of* (P1647) claims, as described in the P1647 documentation [1]. For example, claims like occupation *subproperty of* instance of are invalid. The reasons for this are both technical and architectural. On the technical side, *instance of, subclass of* and *subproperty of* are intended to be straightforwardly exportable as rdf:type, rdfs:subClassOf and rdfs:subPropertyOf. As described in *On the Properties of Metamodeling in OWL* [2], claims that use OWL's built-in vocabulary (e.g. rdf:type) as individuals make an ontology undecidable. If an ontology is undecidable, then queries are not guaranteed to terminate. This is a big deal. Decidability is a main goal of OWL 2 DL and a requirement in the more specialized profiles OWL 2 EL, OWL 2 RL and OWL 2 QL. Most Semantic Web ontologies aim to valid be in at least OWL 2 DL. So if Wikidata aims to be easily interoperable with the rest of the Semantic Web, we should aim to be valid in OWL 2 DL, and thus not make claims of the form P *subproperty of* instance of (P31) or P *subproperty of* subclass of (P279). Avoiding such claims is also good design. There should be one -- and preferably only one -- obvious way to specify the type of an instance. Having a multitude of domain-specific type subproperties would promote an anti-pattern: using *instance of* as a catch-all property to make any statement under the sun that makes sense when connected with the phrase is a. Having a single type property for instances also fosters another best practice in Wikidata: asserted monohierarchy [3]. In other words, there should be only one explicit normal or preferred *instance of *or *subclass of* claim per item. Having an *instance of *claim and a *subclass of* claim on an item isn't necessarily bad (it's called punning), but having multiple *instance of* claims or multiple *subclass of* claims on an item is a bad smell. Items can typically satisfy a huge number of *instance of* claims, but should generally have only one such claim made explicitly in Wikidata. For example, Coco Chanel (Q45661) can be said to be *instance of* French person, *instance of* fashion designer, *instance of* female, etc. Instead of such catch-all use of *instance of*, Wikidata moves that knowledge into properties like *country of citizenship* (P27), *occupation* (P106) and *sex or gender* (P21). Coco Chanel has one explicit *instance of* value: human (Q5) -- a class that encapsulates essential features of the subject. Most of Wikidata follows these general principles of classification. But a few domains of knowledge remain either somewhat of a mess, or organized but idiosyncratic. Items like the one for the German municipality of Aalen [4], with 7 *instance of* values -- several of them redundant -- exemplify the mess. With the deletion of domain-specific type properties like *type of administrative territorial entity* (P132) [5], we are on the right track. The solution is not to make such things subproperties of *instance of*, but rather to delete them and use *instance of* for one preferred class and put other values in other properties (note -- this may require new properties!). The same applies for *subclass of*. I encourage anyone interested in stuff like *subproperty of* to join the discussions ongoing at https://www.wikidata.org/wiki/Wikidata:Property_proposal/Property_metadata. The Wikidata community is currently discussing how we want to handle things like *domain* and *range* properties (e.g. should we use rdfs:domain or schema:DomainIncludes?) and whether we want to have an *inverse of* property (or delete all inverse properties). The outcome of these discussions will shape the interface between Wikidata and the rest of the Semantic Web. Thanks, Eric https://www.wikidata.org/wiki/User:Emw 1.https://www.wikidata.org/wiki/Property:P1647 2.Boris Motik (2007). On the Properties of Metamodeling in OWL.**https://www.cs.ox.ac.uk/boris.motik/pubs/motik07metamodeling-journal.pdf** *3. *Barry
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
On Fri, Jan 9, 2015 at 7:43 PM, Joe Filceolaire filceola...@gmail.com wrote: There is a proposal to create a 'subproperty of' property but it is on hold until we can have a property as a datatype Property datatype is available and the subproperty of property exists: https://www.wikidata.org/wiki/Property:P1647 It is used on the following properties: https://www.wikidata.org/w/index.php?title=Special%3AWhatLinksHeretarget=Property%3AP1647namespace=120 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
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
Since it appears that the creation of *subproperty of* went unnoticed by many, I'd like to describe an important aspect of its proper use, and how that relates to classification. Please note that *instance of* (P31) and *subclass of* (P279) are not valid values for *subproperty of* (P1647) claims, as described in the P1647 documentation [1]. For example, claims like occupation *subproperty of* instance of are invalid. The reasons for this are both technical and architectural. On the technical side, *instance of, subclass of* and *subproperty of* are intended to be straightforwardly exportable as rdf:type, rdfs:subClassOf and rdfs:subPropertyOf. As described in *On the Properties of Metamodeling in OWL* [2], claims that use OWL's built-in vocabulary (e.g. rdf:type) as individuals make an ontology undecidable. If an ontology is undecidable, then queries are not guaranteed to terminate. This is a big deal. Decidability is a main goal of OWL 2 DL and a requirement in the more specialized profiles OWL 2 EL, OWL 2 RL and OWL 2 QL. Most Semantic Web ontologies aim to valid be in at least OWL 2 DL. So if Wikidata aims to be easily interoperable with the rest of the Semantic Web, we should aim to be valid in OWL 2 DL, and thus not make claims of the form P *subproperty of* instance of (P31) or P *subproperty of* subclass of (P279). Avoiding such claims is also good design. There should be one -- and preferably only one -- obvious way to specify the type of an instance. Having a multitude of domain-specific type subproperties would promote an anti-pattern: using *instance of* as a catch-all property to make any statement under the sun that makes sense when connected with the phrase is a. Having a single type property for instances also fosters another best practice in Wikidata: asserted monohierarchy [3]. In other words, there should be only one explicit normal or preferred *instance of *or *subclass of* claim per item. Having an *instance of *claim and a *subclass of* claim on an item isn't necessarily bad (it's called punning), but having multiple *instance of* claims or multiple *subclass of* claims on an item is a bad smell. Items can typically satisfy a huge number of *instance of* claims, but should generally have only one such claim made explicitly in Wikidata. For example, Coco Chanel (Q45661) can be said to be *instance of* French person, *instance of* fashion designer, *instance of* female, etc. Instead of such catch-all use of *instance of*, Wikidata moves that knowledge into properties like *country of citizenship* (P27), *occupation* (P106) and *sex or gender* (P21). Coco Chanel has one explicit *instance of* value: human (Q5) -- a class that encapsulates essential features of the subject. Most of Wikidata follows these general principles of classification. But a few domains of knowledge remain either somewhat of a mess, or organized but idiosyncratic. Items like the one for the German municipality of Aalen [4], with 7 *instance of* values -- several of them redundant -- exemplify the mess. With the deletion of domain-specific type properties like *type of administrative territorial entity* (P132) [5], we are on the right track. The solution is not to make such things subproperties of *instance of*, but rather to delete them and use *instance of* for one preferred class and put other values in other properties (note -- this may require new properties!). The same applies for *subclass of*. I encourage anyone interested in stuff like *subproperty of* to join the discussions ongoing at https://www.wikidata.org/wiki/Wikidata:Property_proposal/Property_metadata. The Wikidata community is currently discussing how we want to handle things like *domain* and *range* properties (e.g. should we use rdfs:domain or schema:DomainIncludes?) and whether we want to have an *inverse of* property (or delete all inverse properties). The outcome of these discussions will shape the interface between Wikidata and the rest of the Semantic Web. Thanks, Eric https://www.wikidata.org/wiki/User:Emw 1. https://www.wikidata.org/wiki/Property:P1647 2. Boris Motik (2007). On the Properties of Metamodeling in OWL. https://www.cs.ox.ac.uk/boris.motik/pubs/motik07metamodeling-journal.pdf *3. *Barry Smith, Werner Ceusters (2011). Ontological realism: A methodology for coordinated evolution of scientific ontologies. Section 1.8: Asserted monohierarchies. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104413/#S9 4. Aalen on Wikidata as of 2015-01-10. https://www.wikidata.org/w/index.php?title=Q3951oldid=184247296#P31 5. https://www.wikidata.org/wiki/Wikidata:Requests_for_deletions/Archive/2014/Properties/1#type_of_administrative_territorial_entity_.28P132.29 ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
On 09.01.2015 19:43, Joe Filceolaire wrote: There is a proposal to create a 'subproperty of' property but it is on hold until we can have a property as a datatype Yes, that's also important. But I was talking aobut a property that would be used to establish a subpropertyOf relation between a Wikidata property entity and an external (RDF/OWL) property as identified by a URL. This would need to be of type URL. It is a bit confusing that both relations have the same colloquial label, but need to be different properties, of course. Maybe I should have called mine subproperty of external property to avoid this confusion. Markus Joe On 9 Jan 2015 16:26, Thad Guidry thadgui...@gmail.com mailto:thadgui...@gmail.com wrote: https://www.wikidata.org/wiki/Property:P279 aka the superclass ... seems to have an equivalent property that refers to http://www.w3.org/2000/01/rdf-schema#subClassOf ??? dunno. Thad +ThadGuidry https://www.google.com/+ThadGuidry ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org mailto:Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
||On 2015/01/09 14:50, Lydia Pintscher wrote: On Thu, Jan 8, 2015 at 6:43 PM, Denny Vrandečić vrande...@gmail.com wrote: Actually, since Wikidata allows now properties on properties, one might easily create an item Disambiguating property and then make a claim instance of - Disambiguating property on the relevant property. there is no need for any extra implementation work. And in fact that already exists ;-) See for example https://www.wikidata.org/wiki/Property:P345 We would want to say that https://www.wikidata.org/wiki/Q6545185 unique identifier is that same as http://www.w3.org/2002/07/owl#InverseFunctionalProperty. In this case a property is an instance of unique identifier (not sub property) so that unique identifier is the same class as InverseFunctionalProperty. We already have https://www.wikidata.org/wiki/Property:P1628 equivalent property. Is there an equivalent class? - Jeff ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
https://www.wikidata.org/wiki/Property:P279 aka the superclass ... seems to have an equivalent property that refers to http://www.w3.org/2000/01/rdf-schema#subClassOf ??? dunno. Thad +ThadGuidry https://www.google.com/+ThadGuidry ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
Re: [Wikidata-l] Disambiguating property [was: Freebase like API with an OUTPUT feature}
There is a proposal to create a 'subproperty of' property but it is on hold until we can have a property as a datatype Joe On 9 Jan 2015 16:26, Thad Guidry thadgui...@gmail.com wrote: https://www.wikidata.org/wiki/Property:P279 aka the superclass ... seems to have an equivalent property that refers to http://www.w3.org/2000/01/rdf-schema#subClassOf ??? dunno. Thad +ThadGuidry https://www.google.com/+ThadGuidry ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l ___ Wikidata-l mailing list Wikidata-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l
