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

[Jan Algermissen]

Murray Altheim wrote:
> 
> Thomas B. Passin wrote:
> > Jan Algermissen wrote:
> [...]
> >> So in a) the URI per definition allways identfies the Web-Resource
> >> (whatever that resource is intended to be in this case)
> >
> > No it does not - the rfc for URIs specifically says that URIs can
> > identify non-retrievable resources, including concepts.  RDF uses URIs
> > as abstract "identifiers" when they appear as values of rdf:about or
> > rdf:ID.
> 
> Tom,
> 
> The problem is the ambiguity, i.e., not being able to reliably infer
> what the author meant. 

The problem is that it is not the author's intenion that matters but
the intention of the authority controling the URI. Topic maps really
do better here, because the allow and make explicit the author's 
intent.

The interoperability problem is that TM authors might use URIs for
documents[1] that some authority actually defined to denote abstract
concepts.

We should not ignore though, that the Web architecture approach has
interesting aspects because all URIs cane be treated in the same way, anytime
and everywhere. That's why I said that you can enter them in the browser's
location bar and be sure what the meaning is of what you get back (if so):
a representation of the identified resource. Technically (for building a huge
distributed system such as the Semantic Web this is not such a bad decision
after all.

Jan

[1] Actually, in TM-land all URIs *address* documents and only the
    context makes the addressed documents subjectIndiocators or
    the addressed subject.

> In not knowing whether 'http://www.w3.org/index.html'
> refers to the W3C as an organization, the W3C home page as an entity,
> or the W3C home page as a resource*, well, that seems like a problem.
> 
> Since the publication of ISO 13250:2000 this has been one of the claims
> of difference between TM and RDF, and it still stands as true, AFAIK.
> 
> Murray
> 
> * I use "entity" to refer to the W3C's home page (as a "home page"),
>    and "resource" to refer to that home page as an XHTML/HTML document.
> ......................................................................
> Murray Altheim                    http://kmi.open.ac.uk/people/murray/
> Knowledge Media Institute
> The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .
> 
>    The world, Bush said, is now riven by "the clearest of divides:
>    between those who seek order and those who spread chaos; between
>    those who work for peaceful change and those who adopt the methods
>    of gangsters; between those who honor the rights of man and those
>    who deliberately take the lives of men and women and children
>    without mercy or shame. Between these alternatives there is no
>    neutral ground."
>    http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2003/09/24/MN298975.DTL
> 
>    Actions speak louder than words, and I think it's pretty clear
>    which side of the divide Bush is on.
> 
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-- 
Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org