Re: Identity of URIRefs / Resources

Jimmy, 
> Very nice and interesting CMS.  I have a simular idea; although, it isn't a
> server side app.  What does WYMIWYG stand for?  What You Make Is What You Get?
Thanks, What You Mean Is What You Get, mainly. 
> 
> > If I understand http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference 
> > correctly, the following graph contains two statements :
> > <snip>
> 
> Yes.  Even if they were the same URIs, though, there would _still be two
> statements_!  They would just be duplicates, but that is allowed in RDF's data
> model.
If I understand things correctly an RDF graph is a *set* of triples, so
duplicates are never part of model even if a serialization may contain
the same triple multiple time.  If the resource with URIRef
"http://gmuer.ch/%C3%BC" would be necessarily the same as the one with
URIRef "http://gmuer.ch/ü" the model would contain only one statement. 
>  
> > Does it make sense that "Two RDF URI references are equal if and only if 
> > they compare as equal, character by character, as Unicode strings.", 
> 
> Yes. That is correct.
> 
> > wouldn't it cause less problems to say "Two RDF URI references are equal
> > if and only if the resolve to the same URI".
> 
> The problem is that two RDF URI references don't have to "resolve" to anything!
>  They could point to a resource that is not network retrievable, for example. 
> For this reason, I think the tag URI scheme is a good idea for most URIs.  See
> <http://taguri.org> for more info on that scheme.
My use of the word "resolve" was misleading. I didn't mean to talk about
dereferencability of the resource but about the valid URI that is
produced with the method describe at
http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference and which is the
same for the two URIRefs in my example.

> 
> > I'm asking because I'm implementing and RDF based CMS [1] where GET and
> > MGET requests are answered according of the properties the requested
> > resource has in the model and I have no way to find out whether the user
> > requested http://gmuer.ch/%C3%BC or http://example.org/��;.
> 
> Take a look at the SPARQL protocol, which provides a standard way of using HTTP
> to get RDF information.  See <http://www.w3.org/TR/rdf-sparql-protocol/> for
> more information.

I'm not sure how I would have to express in a SPARQL-Get query, that I'm
talking about the resource with URIRef http://gmuer.ch/%C3%BC and not
about the one with URIRef http://gmuer.ch/ü.  The same problem applies
for URIQA.

Cheers,
reto

Received on Sunday, 5 June 2005 16:08:21 UTC