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Re: XMLLiteral in OWL

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Thu, 22 Jan 2004 21:06:24 +0000
Message-ID: <40103B50.4060200@hplb.hpl.hp.com>
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: herman.ter.horst@philips.com, www-webont-wg@w3.org, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>


I would be happy with Ians suggestions, although I suspect most readers 
would miss the implicit requirement. There is an explicit requirement to 
list the supported datatypes which I think is the key defence against 
surprising interoperability problems.

Jeremy


Ian Horrocks wrote:

> I believe that we should keep changes to an absolute minimum.
> 
> I don't believe that the change proposed by Herman, or either of the
> first two changes proposed by Jeremy are necessary because they only
> aim to make explicit what is already implicit).
> 
> I believe that we should make the third change proposed by Jeremy,
> i.e., to modify test miscellaneous-205 by deletion of the word "Full"
> from its levels box - this slightly weakens the test and alleviates
> the problem that it may really be incorrect in its current form.
> 
> Ian
> 
> 
> 
> On January 19, herman.ter.horst@philips.com writes:
> 
>>During the last telecon I was actioned with Jeremy and Ian
>>to look at the problem of XMLLiteral in OWL and propose
>>a decision [1].
>>In this message I summarize the problem and the decision
>>that was already proposed during the meeting.
>>(See, e.g., [3-7]  for earlier discussion about this problem.)
>>
>>Problem
>>- The OWL design allows the possibility of doing without 
>>semantic conditions on XMLLiteral.  This is visible in
>>the Test document (see tests 201-205).
>>- S&AS Section 5 (RDF-compatible model-theoretic semantics)
>>does not allow the possibility of doing without semantic
>>conditions on XMLLiteral.  OWL Full interpretations as well
>>as OWL DL interpretations are D-interpretations (from the
>>RDF Semantics document) and thereby always incorporate
>>semantic conditions on XMLLiteral.
>>- This mismatch between S&AS and Test disturbs a bigger
>>point: as is described in the first paragraph of Test,
>>S&AS is the primary normative document about OWL, and
>>Test is a 'subsidiary' document, aiming to give examples
>>and clarification of S&AS.     As I wrote earlier,
>>
>>>If the document
>>>is left with an error like this, how can a reader decide
>>>for any statement of S&AS whether it is reliable?
>>>
>>Example: the RDF graph
>>      v p l
>>      p rdfs:range rdfs:Literal
>>where l is an ill-typed XML literal, is DL and 
>>Full-inconsistent according to S&AS Section 5,
>>whether the datatype map D contains XMLLiteral or not.
>>Test allows the possibility to not include XMLLiteral
>>in the datatype map, in which case this RDF graph
>>becomes consistent for DL or Full.
>>
>>==
>>
>>Proposed solution:
>>
>>incorporate the three changes precisely described in 
>>Jeremy's note "possible compromise on rdf:XMLLiteral" [2]
>>*and* add one sentence to S&AS Section 5 following
>>the sentence just before Section 5.1:
>>  "If, however, any conflict should ever arise between
>>  these two forms, then the Direct Model-Theoretic
>>  Semantics takes precedence."
>>The new sentence following this sentence should express
>>that this applies (so that the direct semantics takes
>>precedence) when XMLLiteral is not in the datatype map.
>>
>>(To summarize, the three changes described by Jeremy in [2]
>>ensure that
>>-an OWL interpretation (S&AS Section 5.2) always assumes
>>XMLLiteral in its datatype map (not mentioning this
>>would misleadingly suggest that this is not necessary)
>>-the datatype map for OWL Full always includes XMLLiteral
>>-Test 205 does not apply to OWL Full.)
>>
>>During the last telecon support for this solution was expressed
>>by Jeremy and me.
>>
>>
>>Herman
>>
>>[1] http://lists.w3.org/Archives/Public/www-webont-wg/2004Jan/0040.html
>>[2] http://lists.w3.org/Archives/Public/www-webont-wg/2003Dec/0100.html
>>
>>[3] http://lists.w3.org/Archives/Public/www-webont-wg/2003Dec/0035.html
>>[4] http://lists.w3.org/Archives/Public/www-webont-wg/2003Dec/0042.html
>>[5] http://lists.w3.org/Archives/Public/www-rdf-comments/2003OctDec/0233.html
>>[6] http://lists.w3.org/Archives/Public/www-webont-wg/2003Dec/0102.html
>>[7] http://lists.w3.org/Archives/Public/www-webont-wg/2003Dec/0106.html
>>
> 
Received on Thursday, 22 January 2004 16:07:32 GMT

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