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Re: comments on ASS

From: Guus Schreiber <schreiber@swi.psy.uva.nl>
Date: Mon, 13 Jan 2003 12:32:06 +0100
Message-ID: <3E22A3B6.3030906@swi.psy.uva.nl>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: WebOnt WG <www-webont-wg@w3.org>

Peter F. Patel-Schneider wrote:
> From: Guus Schreiber <schreiber@swi.psy.uva.nl>
> Subject: comments on ASS
> Date: Sun, 12 Jan 2003 17:22:37 +0000
>>During the delays on the way home from the ftf I had some time for 
>>additional reviewing of the ASS document, also in relation to GUIDE and 
>>I have top main comments. The first point relates to the OWL Lite 
>>production for class axioms, which reads (BTW thanks for the great 
>>cross-ref table!) :
>>axiom ::= 'Class(' classID modality { annotation } { super } ')'
>>modality ::= 'complete' | 'partial'
>>super ::= classID | restriction
>>axiom ::= 'EquivalentClasses(' classID { classID } ')'
>>I thought we had no defined classes in OWL Lite, so shouldn't the 
>>modality always be "partial"? As it is, the production allows a 
>>sameClassAs statement between a class and a restriction, which Guide 
>>expliclty labels as being an OWL DL construction (see the TexasThings 
> OWL Lite has had defined classes from the beginning.   If the Guide
> indicates otherwise, it needs to be fixed.

So, this is a legal OWL Lite axiom according to the AS&S. If, so we have 
to correct this in the Guide.

<owl:Class rdf:ID="TexasThings">
       <owl:onProperty rdf:resource="#locatedIn" />
       <owl:allValuesFrom rdf:resource="#TexasRegion" />

Note that this only holds for restrictions. Set operators or enumeration 
in this type of axiom would be non-lite.

>>The second comment came up when I was revising the Reference document 
>>section on classes. In the Guide we see RDF/XML class axioms such as:
>><owl:Class rdf:ID="WhiteWine">
>>   <owl:intersectionOf rdf:parseType="Collection">
>>     <owl:Class rdf:about="#Wine" />
>>     <owl:Restriction>
>>       <owl:onProperty rdf:resource="#hasColor" />
>>       <owl:hasValue rdf:resource="#White" />
>>     </owl:Restriction>
>>   </owl:intersectionOf>
>>As I understand it the abstract syntax only allows axioms
>>of the form:
>>   <description> <relation> <description>
>>where <description> should be a class name, a restriction or any of the 
>>set-operation constructs, and <relation> should be subClassOf, 
>>sameClassAs, or dinjointWith.
> The Abstract Syntax only allows class axioms of the form
> Class name modality descriptions
> which have different translations depending on the modality and the number
> of descriptions.  Some of these produce owl:sameClassAs; some don't.

Yes, bu the three Class(..) mapping rules alwats produce either a 
subClassOf, a sameClassAs or a disjointWith triple. The RDF/XML example 
I gave does not. So, the problem I have remains.

>>I had alsways thought the Guide examples where a shorthand with an 
>>implicit sameClassAs statement, but this does not seem to be covered by 
>>the ASS document. Did I miss something (not at all unlikely)?
> See above.
>>A final comment about the presentation: the ASS document often uses the 
>>term OWL/DL, where it actually means OWL/DL and OWL/Full.
>>Please make this clear. The difference is only valid for the semantics 
>>sections. BTW: the asbtract should also mention OWL/Full.
> I think that AS&S is fairly clear on this, and does not use DL where Full
> is meant.  If you have any specific cases, I'll fix them.

As I said: mention OWL Full in the abstract, and replace OWL/DL with 
OWL/DL+Full in all the syntax sections.

> peter

A. Th. Schreiber, SWI, University of Amsterdam,
Received on Monday, 13 January 2003 06:38:52 UTC

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