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Re: Can a URI be a resource? If not, the URIs can't identify EVERYTHING

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 25 Sep 2007 20:49:51 -0500
Message-Id: <p06230904c31f69d743ff@[10.100.0.195]>
To: "Nick Gall" <nick.gall@gmail.com>
Cc: www-tag@w3.org

>It's 2:30am in London where I write this, just having read the 
>umpteenth post about Cool URIs, so I may just be halucinating. But 
>it struck me when thinking about the things that a URI can't 
>identify that AFAIK a URI can't identify a URI. Is this true? If so, 
>is it important?

I don't think it is true, because a URI can in principle identi...no, 
refer to, anything at all. Now, however, that said, I don't see any 
way to actually 'attach' a URI to another URI, as it were, in the way 
that it can be attached to a Web page, say. But again, we have other 
ways to refer to URIs: for example, XML schema has the anyURI 
datatype, so you could use a typed literal in RDF to refer to a URI. 
So why use a URI to do it?

>It could be important because without a way to identify a URI, one 
>cannot make (RDF) assertions it.

Technically, RDF doesn't allow a literal to be a subject, but that is 
clearly a bug and is often ignored by modern RDF tools. So ignoring 
it, you could use this to make assertions about a URI.

>  For example, given the http URI
>
>[1] 
><http://ironick.typepad.com/ironick/2007/09/three-kinds-of-.html>http://ironick.typepad.com/ironick/2007/09/three-kinds-of-.html
>
>one might want to assert that it "ends with the letters h,t,m,l" or 
>that it is so many characters long.

"<http://ironick.typepad.com/ironick/2007/09/three-kinds-of-.html>http://ironick.typepad.com/ironick/2007/09/three-kinds-of-.html"^^xsd:anyURI 
mydef:hasLength "65"^^xsd:number .
??

Pat



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Received on Wednesday, 26 September 2007 01:50:07 UTC

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