W3C home > Mailing lists > Public > www-rdf-interest@w3.org > June 2007

Re: What if an URI also is a URL

From: r.j.koppes <rikkert@rikkertkoppes.com>
Date: Wed, 06 Jun 2007 15:35:49 +0200
Message-ID: <4666B835.7050502@rikkertkoppes.com>
To: "Lynn, James (Software Escalations)" <james.lynn@hp.com>
CC: Tim Berners-Lee <timbl@w3.org>, www-rdf-interest@w3.org

Then appendix A in the primer mentions a way of working that is actually 
erroneous:
___
People sometimes use RDF together with a convention that, when a URIref 
is used to identify an RDF resource, a page containing descriptive 
information about that resource will be placed on the Web "at" that URI, 
so that the URIref can be used in a browser to retrieve that 
information. This can be a useful convention in some circumstances, 
although it creates a difficulty in distinguishing the identity of the 
original resource from the identity of the Web page describing it (a 
subject discussed further in Section 2.3)

(2.3 talks about blank nodes)

I can see the logic of this structure being an error, but it also is 
everyday practice and even mentioned as a "suggestion" in the primer.

I think it is clear that one should not use the same URI for both in a 
triple. But is the proposed method of adding the web URL as a literal in 
the object an acceptable solution?

Regards,
Rikkert Koppes

Lynn, James (Software Escalations) wrote:
> But then does the same restriction apply to fragment identifiers? In
> other words if a server returns a fragment for
> http://www.example.com/mophor#me is it unacceptable to use it as a URI
> for oneself?
> 
> J Lynn
> 
> -----Original Message-----
> From: www-rdf-interest-request@w3.org
> [mailto:www-rdf-interest-request@w3.org] On Behalf Of Tim Berners-Lee
> Sent: Wednesday, June 06, 2007 8:29 AM
> To: r.j.koppes
> Cc: www-rdf-interest@w3.org
> Subject: Re: What if an URI also is a URL
> 
> 
> 
> On 2007-06 -06, at 07:30, r.j.koppes wrote:
> 
>>
>> suppose I identfy mysef with the following URI:
>>
>> http://www.example.com/mophor
>>
>> And suppose I have a homepage at http://www.example.com, then we get 
>> the following triple:
>>
>> <http://www.example.com/mophor>
>> <http://xmlns.com/foaf/0.1/homepage>
>> <http://www.example.com>
>>
>> But now suppose, I have a page about myself on my homepage somewhere, 
>> http://www.example.com/mophor, say.
> 
> That is an error.  You cannot use the same URI to identify yourself and
> your home page.
> The moment a server returns 200 OK for a request to the URI, it is
> saying it identifys a document.
> You can't use the same URI for yourself.
> You could use http://www.example.com/mophor#me as a URI for yourself or
> http://www.example.com/mophor/foaf#morphor orhttp://www.example.com/
> mophor/me and have a 303 redirect from their to a document about you.
> 
> Tim BL
> 
> 
Received on Wednesday, 6 June 2007 13:34:35 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:52:19 GMT