Re: Semantic Web archaeology

Thanks Stian, but I know this. My question is why some terms have been 
put in the rdf: namespace rather than rdfs: and vice versa. For instance:

rdf:Property seems to play a role similar to rdfs:Class. When it's used, 
e.g.:

  foaf:knows  a  rdf:Property .

it's totally describing the vocabulary, just like:

  foaf:Person a  rdfs:Class .

But strangely, one is in rdf: the other in rdfs:.

Also, when one writes:

  ex:something  a  rdfs:Resource .

It's very much what is expected in the instance description, not the 
vocabulary (by the way, I avoid using "schema", because RDFS is really 
not describing schemas at all - very bad name).

I've seen *many* people confusingly use "rdf:Resource" instead, and I've 
seen sometimes people using rdfs:Property as well.

Also: rdfs:label, rdfs:comment, rdfs:seeAlso? how is it specific to the 
vocabulary definition?

The spec at https://www.w3.org/TR/PR-rdf-schema/ shows diagrams where 
every terms are in rdfs: except rdf:Property and rdf:type (Fig.1 and 
Fig.2), without any explanation. A beginner may think this is a typo.

There is another question too: why two namespaces after all, considering 
that, apparently, not everyone wanted the 2 namespaces at first?


--AZ

Le 28/06/2019 à 10:50, Stian Soiland-Reyes a écrit :
> On Fri, 28 Jun 2019 09:55:50 +0200, Antoine Zimmermann <antoine.zimmermann@emse.fr> wrote:
>> Recently on Stack Overflow, there was a question asking "Why rdf:Seq and
>> not rdfs:Seq?" [1]. I tried to answer the best I could, by digging in
>> the old RDF mailing lists, but I am still puzzled about how some terms
>> ended up in the rdf: namespace rather than rdfs: (and vice versa). Can
>> someone involved in the early days of RDF enlighten us about this?
> 
> Not involved at time, but rdfs: is all about the schema, *describing*
> properties and types. It is a mini-ontology-language.  rdf: is about
> using the language.
> 
> Here is how rdf was introduced in 1999
> https://www.w3.org/TR/1999/REC-rdf-syntax-19990222/
> 
> ..which links to rdfs draft https://www.w3.org/TR/PR-rdf-schema/
> co-developed separately, but rdfs took significantly more time to
> formalize.
> 
> Dan Brickley may be able to fill me in, but I believe it was the
> intention a that using rdfs was optional? (you could mint
> http://example.com/vocab#property5 and just have a HTML page about it)
> 
> rdf:Seq is a data construct, so part of rdf like Bag and List
> (BTW, describing use of rdf:Seq in rdfs is difficult, as you cannot say
> what elements are expected in the seq.)
> 
> So you could say rdfs: is at "meta" level, describing what *could* be
> used in RDF instances (or more like, what do the terms mean), while rdf:
> is a practitioner level, properties and types you may use in regular RDF
> "instance-level" documents.
> 
> 

-- 
Antoine Zimmermann
Institut Henri Fayol
École des Mines de Saint-Étienne
158 cours Fauriel
CS 62362
42023 Saint-Étienne Cedex 2
France
Tél:+33(0)4 77 42 66 03
Fax:+33(0)4 77 42 66 66
http://www.emse.fr/~zimmermann/
Member of team Connected Intelligence, Laboratoire Hubert Curien

Received on Friday, 28 June 2019 09:53:41 UTC