- From: Pat Hayes <phayes@ihmc.us>
- Date: Mon, 13 Aug 2012 14:42:32 -0500
- To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
- Cc: Richard Cyganiak <richard@cyganiak.de>, RDF Working Group WG <public-rdf-wg@w3.org>, Simon Reinhardt <simon.reinhardt@koeln.de>
On Aug 13, 2012, at 12:29 PM, Antoine Zimmermann wrote: > I know this is a very old email but I'm catching up now with some of the > WG's email I left unread. There is an inaccuracy in what you say Richard. > > > Le 26/04/2012 02:00, Richard Cyganiak a écrit : >> All, >> >> Simon Reinhardt spotted [1] a nice little contradiction between the >> 2004 versions of RDF Concepts and RDF Semantics. >> >> RDF Concepts states, in a normative section [2]: >> >> [[ The predicate is also known as the property of the triple. ]] >> >> Where “predicate” is defined as a URIref, one of the three components >> of a triple. RDF Semantics, on the other hand, defines [3]: >> >> [[ A simple interpretation I of a vocabulary V is defined by … a set >> IP, called the set of properties of I. ]] >> >> And the rest of the mechanics make it clear that URIrefs can denote a >> member of IP. In other words, RDF Concepts says that the predicate >> IRI *is* the property, while RDF Semantics says that it *denotes* the >> property. >> >> The analogy with classes shows IMO that RDF Concepts is wrong and RDF >> Semantics is right. The IRI<http://xmlns.com/foaf/0.1/Person> *is* >> not a class, but it *denotes* a class. >> >> I therefore deleted the normative definition quoted above from the >> RDF Concepts ED. If you disagree with this change or see further need >> to discuss this, then please respond. >> >> Note that the new Introduction section in the RDF Concepts ED >> contains an *informative* sentence that introduces the term >> “property” [4], and it is in line with RDF Semantics: >> >> [[ The predicate itself is an IRI and denotes a binary relation, also >> known as a property. ]] > > > This is not what the RDF semantics says. A predicate denotes a resource that must be in IP, the set of properties in the interpretation. Resources in IP are associated with a binary relation via the extension function IEXT. > This is an important distinction since this is what allows RDF to talk about properties, classes, etc as instances. > > If predicates were denoting binary relations, the following would be RDFS-inconsistent, when it is, in fact, RDFS-consistent: > > :p rdf:type xsd:string . > :s :p :o . > > This is a proposal to replace the wording in section 1.2 [1]: > > "The predicate itself is an IRI and denotes a property, that is, a resource that defines a binary relation." +1. Good catch, Antoine. Pat > > > > [1] 1.2 Resources and Statements. http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#resources-and-statements > > AZ > >> >> Best, Richard >> >> >> [1] >> http://lists.w3.org/Archives/Public/public-rdf-comments/2012Mar/0008.html >> >> > [2] http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#section-triples >> [3] http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#gddenot [4] >> http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#dfn-property >> >> > -- > Antoine Zimmermann > ISCOD / LSTI - Institut Henri Fayol > École Nationale Supérieure des Mines de Saint-Étienne > 158 cours Fauriel > 42023 Saint-Étienne Cedex 2 > France > Tél:+33(0)4 77 42 66 03 > Fax:+33(0)4 77 42 66 66 > http://zimmer.aprilfoolsreview.com/ > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Monday, 13 August 2012 19:43:05 UTC