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AW: Requirements for a possible "RDF 2.0"

From: Sauermann Leo <leo.sauermann@gnowsis.com>
Date: Wed, 27 Jan 2010 10:23:55 +0000
To: Chris Welty <cawelty@gmail.com>, "semantic-web@w3.org" <semantic-web@w3.org>
Message-ID: <50F7AB249E98E547A3A8765156959A2C0291BA@VEX10STORE1.workplace.netmonic.com>
I thought about some things that I noticed in the last 6 years of banging my head against RDF. I post them here just for reference, maybe someone needs them during the workshops or so.

Blogged here:
http://leobard.twoday.net/stories/6158833/

Leobard's thoughts about needed changes to RDF.

Problems:

1) Reification is not an aesthetically appealing model because it forces the triple/statement structure on quads. Therefore it is not used much and discouraged by some "named graph" enthousiasts. Nevertheless, the need to identify and annotate single triples and their values is there.

2) rdf:value, datatype, language, and reification all address the same need and are redundant.

3) The relation between a web resource (i.e. a web page in html) and the RDF document (named graph) containing the RDF data of the web page can NOT be expressed with the RDF standard. There exist various, scarcely documented methods such as the HTML Header tag "" or 303 redirects, or content negotiation. Some of these methods are described in "Cool Uris for the Semantic Web"). This has been causing personal bellyaches for me since editing "Cool Uris for the Semantic Web". It is not aesthetic as this central feature of linked data and RDF can't be represented in RDF.

4) Statements about reified triples must be possible for sets of triples.

Suggestions for Solutions: [syntax: problem->solution]

1)->S1) On the core level of RDF, add an URI identifier to a triple. Let Serializations allow to add this URI to the triple. Add a triple identifier to the core of the spec and APIs.

2)->S2) Deprecate rdf:value.

3)->S3) In RDFS we already hint at HTTP dereferenciation and linked data in rdfs:seeAlso and its subproperty rdfs:isDefinedBy. In foaf we have foaf:homepage that links a resource to its web page. In SKOS we had skos:isSubjectOf (but it was removed) I propose """ rdfs:describes a rdfs:Property; rdfs:domain rdfs:Resource; rdfs:range rdfs:Resource; rdfs:comment "The subject RDF resource is metadata for the object document." """ . This solution seems to add problems though, as the relation between document and resource is dynamic and ever changing.

3)->S3.1) Leave it as is. The problem of linking between HTML and RDF representations is on the level of HTML and not on RDF.

-----Ursprüngliche Nachricht-----
Von: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] Im Auftrag von Chris Welty
Gesendet: Mittwoch, 13. Januar 2010 17:00
An: semantic-web@w3.org
Betreff: Requirements for a possible "RDF 2.0"



Without volunteering myself to be such a contact, I have (as both a
users of many RDF implementations and a W3C chair and I suppose a
self-declared semantic web expert) been the recipient of a lot of
complaints and suggestions regarding the design and implementation of
RDF, and at ISWC a few months ago I suggested to Ivan that we start
discussing starting a working group that would investigate a next
version of RDF.

This discussion is happening in several places already, and we thought
this was the best place to house that discussion for now.

A workshop on this subject is also in the planning, more news on that in
a week or two.

I suppose we don't really need to discuss whether we should investigate
an "RDF 2.0", but rather what kinds of requirements various RDF users
have that they would like to be considered (I'd like this thread to be
less "+1" and "-1" messages, and more "I'd like to see RDF support x...")

-Chris

--
Dr. Christopher A. Welty                    IBM Watson Research Center
+1.914.784.7055                             19 Skyline Dr.
cawelty@gmail.com                           Hawthorne, NY 10532
http://www.research.ibm.com/people/w/welty
Received on Wednesday, 27 January 2010 10:24:44 GMT

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