Print

Print


Am 16.11.2015 um 22:14 schrieb Denenberg, Ray:
> Karen,  take this one step at a time.  Suppose I have a triple:
> 
>      <some subject>   bf:someProperty   <http://someURI>
> 
> Where again I am using turtle notation and I am explicitly enclosing
> http://someURI  in angle braces.   I claim that http://someURI
> (enclosed in angle braces) must be dereferenceable as RDF (meaning
> that there is an RDF representation of that resource, http://someURI,
> which may be one of many representations, and I can get that RDF
> representation by doing a get on it requesting RDF via content
> negotiation).

No. You may be alluding to the concept of "information resources" when
distinctions between Real World Object and Web Content describing
them comes into play. But these may be anything and are not restricted
to RDF.

I would say, already thinking in lines of "an RDF representation of
that resource" is alien to RDF: Having <http://someURI> in object
position of a statement implies that there is an entity which can
be identified by that IRI. So somewhere in the world there may
exists statemtents with <http://someURI> in subject position, or
there may not. That the sum of these statements yields a (complete?)
description of that entity or even that there is (at least) some
single place where a description in the sense of several RDF triples
for that IRI exist, is not implied. If so, we would have the case
of an information resource again, but stating that there is an
associated information resource on the web for <http://someURI>
would mandate the coining of a different IRI since at that point
we have to differentiate between the resource and its description
as another resource. There is a standard practice with fragment
identifiers to achieve that without effort.

The hassle with IRIs (<bracketed>, as identifiers in RDF context)
against URIs as strings in "quotes" is based on our attempts to
encompass the concept of "Real World Identifiers" (a notion probably
originally koyned here): Since we are expecting to "see" that
 https://viaf.org/viaf/174144647695570462777/
"is" a VIAF identifier (or a canonical URI for the VIAF identifier
"174144647695570462777" or an alternative representation for the
abstract VIAF identifier of VIAF identifier datatype behind that) or
that "urn:isbn:0-486-27557-4" refers to a resource which also will
be unanimously identified by the ISBN 0-486-27557-4. For that we
need /inspection/ of the URIs and that is due to opaqueness not
possible for the bracketed Identifiers in the RDF sense.

viele Gruesse
Thomas Berger