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Re: comments on Web Architecture First Edition

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Sat, 08 May 2004 20:53:57 +0100
Message-ID: <409D3AD5.7060400@hplb.hpl.hp.com>
To: Pat Hayes <phayes@ihmc.us>
Cc: "Roy T. Fielding" <fielding@gbiv.com>, public-webarch-comments@w3.org, w3c-rdfcore-wg@w3.org


A very minor point:

Pat Hayes wrote:
> It seems to identify 'access' with 'identify', for example where it says
> 
> "A URI must be assigned to a resource in order for agents to be able to 
> refer to the resource. It follows that a resource should be assigned a 
> URI if a third party might reasonably want to link to it, make or refute 
> assertions about it, retrieve or cache a representation of it, include 
> all or part of it by reference into another representation, annotate it, 
> or perform other operations on it."
> 

The quoted paragraph is untrue (the word "must").
OWL permits reference to uniquely identified resources without them 
having a URI. (through the use of functional and inverse functional 
properties)
Suggest a minimal rewording of insert "easily"
i.e.
"A URI must be assigned to a resource in order for agents to be able to
  easily refer to the resource. It follows that a resource should be 
assigned a  URI if a third party might reasonably want to link to it, 
make or refute assertions about it, retrieve or cache a representation 
of it, include  all or part of it by reference into another 
representation, annotate it, or perform other operations on it."

Although my preference would be to take Pat's comments seriously which 
may require greater rewording.



>> Where does it say that all resources have a unique identifier?
> 
> 
> Sorry about that last one, I phrased it badly. I know the document does 
> not say that resources have a unique URI, ie that URIs cannot converge 
> in identification; in fact it explicitly denies it. What I should have 
> said is that the idea that resources must be identified by an 
> unambiguous URI has no rational basis, etc.. As I have explained in 
> earlier emails, with examples, it is not necessary to have an identifier 
> for something in order to refer to it.

OWL's use of Functional and InverseFunctional Properties is a simple 
example of this, I can flesh this out if it is helpful.

Jeremy
Received on Saturday, 8 May 2004 15:54:40 EDT

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