Am 04.09.2018 um 19:19 schrieb Robert Sanderson: > In particular, it makes it difficult in several serializations to distinguish > between the string “http://example.museum.org/data/1” and the resource that > has the URI http://example.museum.org/data/1 as its identifier.
Which ones do you mean? All the serializations I've seen make clear syntactic distinctions between literals and URIs. While I agree that "punning" is bad practice, I don't see why it should confuse RDF software tools. Detlev Am 04.09.2018 um 19:19 schrieb Robert Sanderson: > > > Dear all, > > > > Please no! This is called “punning” (when the same property can be have both > literals and resources as its range) and is widely recognized as a bad > practice in RDF. > > > > In particular, it makes it difficult in several serializations to distinguish > between the string “http://example.museum.org/data/1” and the resource that > has the URI http://example.museum.org/data/1 as its identifier. > > > > Rob > > > > > > *From: *Crm-sig <crm-sig-boun...@ics.forth.gr> on behalf of Martin Doerr > <mar...@ics.forth.gr> > *Date: *Saturday, September 1, 2018 at 7:41 AM > *To: *crm-sig <Crm-sig@ics.forth.gr> > *Subject: *[Crm-sig] Issue: Solution for Dualism of E41 Appellation and > rdfs:label > > > > Dear All, > > Obviously, there are two ways in RDF to express what the CRM regards as an > Appellation: Either using a URI, instance of E41, and then another property > specifying in whatever way the symbolic content (I am not concerned with this > here), *OR *using rdfs:label, which has exactly the meaning of some forms of > Appellation that can be expressed exhaustively as literal. > > Interesting enough, there seems to be no existing validation method, that > would exclude any instance of xsd Datatype to be used as range of rdfs:label. > > We have made therefor the following tests with Virtuoso, if P1 can have two > ranges, Literal and E41, and if SPARQL gives the expected answers, it does: > > > *1.** **Dualism of Appellations* > > The purpose of this is to provide an *RDF based technical solution* for > representing and querying a property which can be at the same time Data and > Object type regardless of the fact that it violates the respective > constraints or rules. > > Practically we can have three options of representing appellations. By taking > the example of Alexander the Great with supposed URI: > http://example.com/person/alexander_the_great we can do the following: > > 1) Use the “P1 is identified by” property and an instance of E41 > Appellation class: > > > > <http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> > > crm:P1_is_identified_by > > <http://example.com/appellation/alexander_the_great> > <http://example.com/appellation/alexander_the_great> . > > > > <http://example.com/appellation/alexander_the_great> > <http://example.com/appellation/alexander_the_great> > > rdfs:label > > "Alexander the Great" . > > > > 2) Use directly the rdfs:label: > > <http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> > > rdfs:label > > "Alexander the Great" . > > > > 3) Use the “P1 is identified by” property as a data property (violating > the rdfs definitions): > > <http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> > > crm:P1_is_identified_by > > "Alexander the Great" . > > > > Based on these examples the following steps were followed to test the > practical application of such cases to a triple store. *Virtuoso triple > store* was used for the following examples. > > 1. The cidoc_crm.rdfs was altered to include the following: > > <rdf:Property rdf:about="P1_is_identified_by"> > > <rdfs:label xml:lang="en">is identified > by</rdfs:label> > > <rdfs:domain rdf:resource="E1_CRM_Entity"/> > > <rdfs:range rdf:resource="E41_Appellation"/> > > </rdf:Property> > > <rdf:Property rdf:about="P1_is_identified_by"> > > <rdfs:label xml:lang="en">is identified by</rdfs:label> > > <rdfs:domain rdf:resource="E1_CRM_Entity"/> > > <rdfs:range > rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"; > <http://www.w3.org/2000/01/rdf-schema#Literal>/> > > </rdf:Property> > > * * > > So, an is identified property was added to the initial schema but with > rdfs:Literal as a range. > > > > 2. The cidoc crm schema was uploaded in virtuoso and the following > query (give me the range of P1_is_identified_property) was executed to be > sure that the changes have been applied: > > > > prefix crm: <http://www.cidoc-crm.org/cidoc-crm/> > <http://www.cidoc-crm.org/cidoc-crm/> > > prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> > <http://www.w3.org/2000/01/rdf-schema> > > > > select * where { crm:P1_is_identified_by rdfs:range ?range} > > > > *result: * > > *range* > > http://www.cidoc-crm.org/cidoc-crm/E41_Appellation > > http://www.w3.org/2000/01/rdf-schema#Literal > > > > So, it is confirmed that the two ranges have been added. I repeat at this > point that Virtuoso *does not apply* any semantic validation. The purpose of > this test is to prove that this exercise is possible even though conceptually > it may not be correct. > > > > 3. The ttl data that was presented previously has been added in > virtuoso: > > > > @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> > <http://www.w3.org/2000/01/rdf-schema> . > > @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> > <http://www.w3.org/1999/02/22-rdf-syntax-ns> . > > @prefix crm: <http://www.cidoc-crm.org/cidoc-crm/> > <http://www.cidoc-crm.org/cidoc-crm/> . > > > > <http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> > > crm:P1_is_identified_by <http://example.com/appellation/alexander_the_great> > <http://example.com/appellation/alexander_the_great> . > > > > <http://example.com/appellation/alexander_the_great> > <http://example.com/appellation/alexander_the_great> > > rdfs:label "Alexander the Great" . > > > > <http://example.com/person/alexander_the_great> > > rdfs:label "Alexander the Great" . > > > > <http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> > > crm:P1_is_identified_by "Alexander the Great" . > > > > 4. A query to return all the “identifiers” of alexander the great using > the is identified property was applied: > > prefix crm: <http://www.cidoc-crm.org/cidoc-crm/> > <http://www.cidoc-crm.org/cidoc-crm/> > > prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> > <http://www.w3.org/2000/01/rdf-schema> > > select * where > > { <http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> crm:P1_is_identified_by > ?identifier } > > *result: * > > *identifier* > > http://example.com/appellation/alexander_the_great > > Alexander the Great > > > > So, it is obvious that with the same query both the literal and the uri > values are returned. > > A version of the above query to return also the appellation’s label (but not > the uri) is the following: > > prefix crm: <http://www.cidoc-crm.org/cidoc-crm/> > <http://www.cidoc-crm.org/cidoc-crm/> > > prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> > <http://www.w3.org/2000/01/rdf-schema> > > select ?identifier > > where { > > {<http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> crm:P1_is_identified_by > ?identifier } > > UNION > > {<http://example.com/person/alexander_the_great> > <http://example.com/person/alexander_the_great> crm:P1_is_identified_by > ?identifier_uri . > > ?identifier_uri rdfs:label ?identifier } > > FILTER (!isURI(?identifier)) > > } > > *With the following result :* > > *I**dentifier* > > Alexander the Great > > Alexander the Great > > > > The next question is, if P1 can be declared superproperty of rdfs:label, so > that the query for P1 returns everything CRM regards as Appellation. It works: > > > > It was tested by altering the cidoc-crm rdfs file, importing it in virtuoso > and asking for the subproperties of rdfs:label as follows: > > <rdf:Property rdf:about="P1_is_identified_by"> > > <rdfs:label xml:lang="en">is identified by</rdfs:label> > > <rdfs:label xml:lang="ru">идентифицируется посредством</rdfs:label> > > <rdfs:label xml:lang="fr">est identifiée par</rdfs:label> > > <rdfs:label xml:lang="pt">é identificado por</rdfs:label> > > <rdfs:domain rdf:resource="E1_CRM_Entity"/> > > <rdfs:range rdf:resource="E41_Appellation"/> > > * <rdfs:subPropertyOf > rdf:resource="http://www.w3.org/2000/01/rdf-schema#label"; > <http://www.w3.org/2000/01/rdf-schema#label>/>* > > </rdf:Property> > > Query (Give me all the subproperties of rdfs:label) : > > select * where { > > ?p rdfs:subPropertyOf rdfs:label > > } > > Result from Virtuoso: > > p: > > http://www.cidoc-crm.org/cidoc-crm/P1_is_identified_by > > > > I propose this method for the RDFS implementation of the CRM: two ranges for > P1, namely E41 and rdf:Literal, and P1 superproperty of rdfs:label. > > Best, > > > > Martin > > -- > > -------------------------------------------------------------- > > Dr. Martin Doerr | Vox:+30(2810)391625 | > > Research Director | Fax:+30(2810)391638 | > > | Email: mar...@ics.forth.gr > <mailto:mar...@ics.forth.gr> | > > | > > Center for Cultural Informatics | > > Information Systems Laboratory | > > Institute of Computer Science | > > Foundation for Research and Technology - Hellas (FORTH) | > > | > > N.Plastira 100, Vassilika Vouton, | > > GR70013 Heraklion,Crete,Greece | > > | > > Web-site: http://www.ics.forth.gr/isl | > > -------------------------------------------------------------- > > > > _______________________________________________ > Crm-sig mailing list > Crm-sig@ics.forth.gr > http://lists.ics.forth.gr/mailman/listinfo/crm-sig > -- Detlev Balzer, Mecklenburger Landstr. 5, D-23570 Lübeck Tel (+49/0)4502-8896495, Mobil (+49)0173-6231233 PGP Fingerprint B5F3 6467 0615 1EB4 B602 8E41 DE70 8D59 0A8B BBD7
