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Re: comments on ASS

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 13 Jan 2003 05:48:36 -0500 (EST)
Message-Id: <20030113.054836.70413764.pfps@research.bell-labs.com>
To: schreiber@swi.psy.uva.nl
Cc: www-webont-wg@w3.org

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 
> REF.
> 
> 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 
> example).

OWL Lite has had defined classes from the beginning.   If the Guide
indicates otherwise, it needs to be fixed.

> 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>
> </owl:Class>
> 
> 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.

> 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.

> Guus

peter
Received on Monday, 13 January 2003 05:48:49 GMT

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