[topicmapmail] Meaning of URIs - ongoing debate on new W3C forum

[Jan Algermissen]

"Thomas B. Passin" wrote:
> 
> Jan Algermissen wrote:
> 
> >
> > Yes, the whole point was to demonstrate that in RDF the URI allone is sufficient
> > to know what the URI identifies [1] because there is only *one* addressing context.
> > In TM-land we have two different addressing contexts ('use-URI-as-subject-address
> > and 'use-URI-as-subjectIdentifier'), so the URI alon is not sufficient to know what
> > it identifies.
> >
> 
> But as I have just posted, you still have to know how the uri is being
> used in an rdf data set.  What you say above is so in the case that a
> uri is used as the value of rdf:about or rdf:ID, but there are plenty of
> other places that a uri could appear and it would not "mean" the same
> thing.  Thus rdf has its "addressing contexts" as well.

No. The meaning of a URI is not dependent of the context in which it
is used. The authority controling that URI **defines** what it denotes!
Crazy, yes. But that is how it (currently) is.

> 
> Here's an example (omitting namespace declarations) -
> 
> <ex:organization rdf:about='uri:orgCentral:orgs#w3c'>
>     <ex:homepage>http://www.w3.org/index.html</ex:homepage>
> </ex:organization>
> 
> This snippet says that a node in an rdf graph identified by the string
> 'uri:orgCentral:orgs#w3c' has a property identified by the string
> "ex:homepage" with a value of "http://www.w3.org/index.html".

Ok, but if the W3C defined "http://www.w3.org/index.html" to 
denote itself then you run into semantical errors here. You cannot,
as an RDF author, **assume** that "http://www.w3.org/index.html"
denotes a web page.


Jan
> 
> Any binding of 'uri:orgCentral:orgs#w3c' to the real W3C has to take
> place outside of rdf, because rdf has no such binding mechanism.
> 
> Cheers,
> 
> Tom P
> 
> _______________________________________________
> topicmapmail mailing list
> topicmapmail@infoloom.com
> http://www.infoloom.com/mailman/listinfo/topicmapmail

-- 
Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org