- From: Thomas Baker <tom@tombaker.org>
- Date: Wed, 9 May 2012 17:53:19 -0400
- To: Richard Cyganiak <richard@cyganiak.de>
- Cc: RDF Working Group WG <public-rdf-wg@w3.org>
On Wed, May 09, 2012 at 09:49:29PM +0100, Richard Cyganiak wrote: > > I accept the analogy, but I'm unsure what you mean by "most of the > > sequences in the namespace" not having referents. If you mean "potential > > sequences" then of course that is true. But "namespace," as I see it being > > used, implies a set of IRIs explicitly "declared" by the namespace's > > "owner." > > Well, that's not the way I see it. I understand a namespace as the set of > *all* IRIs starting with the namespace IRI. That seems awfully theoretical, at odds with existing usage of "namespace", sloppy and inconsistent though it may be. > How about this other approach? There's no such thing as a ?namespace? in RDF. > Just avoid the term on its own ? it's a remnant of the old XML baggage. Some > of the other related XML terms that came along with it have proven to be > useful though: Some RDF syntaxes offer a way of associating ?namespace > prefixes? with ?namespace IRIs? in order to abbreviate IRIs; and there's > ?namespace documents? which describe the terms in an RDF vocabulary all of > whose terms start with the same IRI. The term ?namespace? on its own is just > a sloppy way of referring either to such an RDF vocabulary or to a namespace > IRI. +1 - I like this! Keep "namespace" as an adjective. Discourage its use as a noun by saying that "namespace" has no formal meaning in RDF and that when used informally, usage is inconsistent. And above all, avoid using "namespace" as a noun in the formal specs. > >>> Also, the current draft of RDF Concepts 1.1 [1] still says: > >>> > >>> "Vocabulary terms in the rdf: namespace are listed and described in > >>> detail..." > >>> > >>> This suggests that the "rdf: namespace" holds not just any IRIs, but > >>> "vocabulary terms" denoted by IRIs. > >> > >> That's not a valid inference. It says that *some* of the things in the rdf: > >> namespace are vocabulary terms. It doesn't say that all of the things in the > >> rdf: namespace are vocabulary terms. > > > > Strictly speaking, I do not think the sentence says that _all_ of the things > > in the rdf: namespace are vocabulary terms. But it also does not say that all of > > the vocabulary terms in the rdf: namespace are listed and described in detail. > > Not sure what your point is. Really only that the natural-language sentence can be understood in different ways (and mostly by people not attuned to what may be "validly inferred"). But I see you have removed the section from Concepts 1.1 for folding into the RDF Schema document. > > It is not incorrect, then, to use the same IRI both as a namespace IRI > > and to denote a vocabulary? > > It's not incorrect and it is fairly common practice AFAICT. And that's fine with me. The confusing bit, I think, is that "namespace IRI" = "vocabulary IRI" however "namespace" != "vocabulary" > >> [[ > >> An OWL ontology is a formal description of a domain of interest, and can be > >> used to describe the terms in an RDF vocabulary and their relationships. OWL > >> ontologies can themselves be expressed as RDF graphs, using terms in the owl: > >> namespace. OWL is more expressive, but also more complex, than RDF Schema. In > >> fact, OWL contains RDF Schema as a simple subset. > >> ]] > > > > Fine, but that's an OWL ontology. > > > > What about "ontology"? > > I won't go anywhere near that question. > > > Does "ontology" mean "OWL ontology"? > > I suppose every OWL ontology is an ontology? But obviously there are other kinds of ontologies, and there's ontology as a branch of philosophy. > > > Is [1] an ontology? > > It's a (manifestation of an) OWL ontology. Every OWL ontology is an ontology. Therefore, [1] is an ontology. > > > Does its use of "owl:equivalentProperty" make it an "OWL" ontology? > > It doesn't need to use any OWL vocabulary to be an OWL ontology. As I said: ?OWL contains RDF Schema as a simple subset.? +1 - Okay, I get it. > (Strictly speaking, an RDF document doesn't even need to define any classes > or properties to be an OWL ontology. *Any* RDF document is a (degenerate) OWL > document. But that's just sort of an accident in the way OWL is defined.) Also fine. I do not think this necessarily belongs in RDF 1.1 but I'd love to see it clarified _somewhere_. Tom -- Tom Baker <tom@tombaker.org>
Received on Wednesday, 9 May 2012 21:53:53 UTC