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Re: significant problem for moving OWL to Last Call

From: Dan Connolly <connolly@w3.org>
Date: 27 Mar 2003 09:52:16 -0600
To: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com>
Cc: herman.ter.horst@philips.com, www-webont-wg@w3.org
Message-Id: <1048780336.15078.1.camel@dirk.dm93.org>

On Thu, 2003-03-27 at 08:49, Peter F. Patel-Schneider wrote:
> Herman ter Horst just brought to my attention a significant change to the
> RDFS semantics in the editor's version of the RDF semantics document.  

Our last call spec can't cite their editor's version anyway.

> This change involves adding new constructs to the definition of RDFS
> interpretations as follows:
> 
>  	An rdfs-interpretation of V is an rdf-interpretation 
> 	I of (V union rdfV union rdfsV) *with a distinguished subset IC 
> 	of the universe and a mapping ICEXT from IC to the set of 
> 	subsets of IR*, which satisfies the following semantic 
> 	conditions and all the triples in the subsequent table, 
> 	called the RDFS axiomatic triples.  [Emphasis added]
> 
> Previously RDFS interpretations used the same structure as RDF
> interpretations, and IC and ICEXT were conveniences only.
> 
> To track this change will require significant changes to S&AS.  I do not
> feel that OWL can go to last call without some resolution of this new
> issue.
> 
> Peter F. Patel-Schneider
> Bell Labs Research
> Lucent Technologies
> 
> PS:  If I had my druthers, I would change RDFS interpretations back to
> being just like RDF interpretations as they were in the Last Call version
> of the RDF semantics.

That's the only spec available for us to cite anyway.

>   If a clarification is needed I would proceed
> somewhat along the lines of defining rdfs-interpretations as
> 
>  	An rdfs-interpretation of V is an rdf-interpretation I of (V union
> 	rdfV union rdfsV) which satisfies the following semantic conditions
> 	and all the triples in the subsequent table, called the RDFS
> 	axiomatic triples.  For convenience, and to make the semantic
> 	conditions easier to understand, ICEXT is defined as
> 		ICEXT(x) = { y | <y,x> is in IEXT(I(rdf:type)) }
> 	and IC is defined as
> 		IC = { y | <y,I(rdfs:Class)> is in IEXT(I(rdf:type)) }
> 	which is the same as saying
> 		IC = ICEXT(I(rdfs:Class))
> 
> and then removing the second semantic condition.  I would also remove the
> discussion of IC and ICEXT before the definition of an rdfs-interpretation,
> but not the discussion of a class, although minor changes would need to be
> made there.
> 
> PPS:  Someone in the RDF Core WG may want to forward this message to the WG.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 27 March 2003 10:52:21 GMT

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