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Re: RDF Semantics: corrections

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 13 Jan 2004 16:53:48 -0500 (EST)
Message-Id: <20040113.165348.100278587.pfps@research.bell-labs.com>
To: phayes@ihmc.us
Cc: herman.ter.horst@philips.com, jjc@hpl.hp.com, hendler@cs.umd.edu, schreiber@swi.psy.uva.nl, connolly@w3.org, sandro@w3.org, www-rdf-comments@w3.org, bwm@hplb.hpl.hp.com

From: pat hayes <phayes@ihmc.us>
Subject: Re: RDF Semantics: corrections
Date: Tue, 13 Jan 2004 15:36:29 -0600

[...]


> For clarification, my question to you was concerned with the effects 
> on OWL rather than on RDF as such. I was not meaning to ask your 
> opinion on the change in a general sense: as indicated, I will take 
> responsibility for that. I was asking you only to give an opinion on 
> whether the suggestion made by Herman for a 'protective' modification 
> to the *text* of the OWL document is indeed sufficient to ensure that 
> the RDF and OWL specs, with these changes, will still be compatible. 
> The intention is that this will make no change to OWL itself.

Well, you are really asking for us to approve both the change to RDF and
related change to OWL to insulate OWL from the effect of the change to
RDF.  From what I see about the changes I would vote against both.

[...]

> The substantive change is that, as noted above, the class extension 
> of a datatype name is required to contain only the denotations of 
> typed literals in the vocabulary, rather than required to *be* the 
> value space of the datatype. This brings D-interpretations in line 
> with the way that XML typed literals are treated in the RDF 
> semantics, which imposes no explicit requirements on 
> ICEXT(I(rdf:XMLLiteral))
> 
> The only example I am aware of which makes the change visible is this:
> 
> ex:a ex:p "true"^^xsd:boolean .
> ex:a ex:p "false"^^xsd:boolean .
> ex:c rdf:type xsd:boolean .
> 
>   |=?=
> 
> ex:a ex:p ex:c .

What about 

ex:a ex:p "2"^^xsd:short .

|=?=

ex:a ex:p _:a .
_:a rdf:type xsd:int .

I think that this is a valid {xsd:short,xsd:int}-entailment in the PR
version of RDF but would not be valid under the proposed change.

[...]

peter
Received on Tuesday, 13 January 2004 16:57:56 UTC

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