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Re: Some comments on OWL Reference

From: Yuzhong Qu <yzqu@seu.edu.cn>
Date: Fri, 25 Apr 2003 20:28:59 +0800
Message-ID: <001101c30b26$3f32c320$9c0b77ca@xobjects>
To: "Guus Schreiber" <schreiber@cs.vu.nl>
Cc: "webont-comments" <public-webont-comments@w3.org>

It's acceptable.

Thanks for your clarification on rdf:resource and rdfs:Resource.

Yuzhong Qu

> Yuzhong Qu commented:
> http://lists.w3.org/Archives/Public/public-webont-comments/2003Apr/0024.html
> 
>  >  1. The PRECISE SYNTAX  of OWL
>  >
> 
> [..]
> 
> This comment was answered by Jeremy Carrol:
> http://lists.w3.org/Archives/Public/public-webont-comments/2003Apr/0052.html
> 
> 
>  >  2. The domain and range of owl:equivalentClass in OWL Lite.
>  >
>  >  [    3.2.2 owl:equivalentClass
>  >      ...
>  >      NOTE: OWL DL does not put any constraints on the types of class
>  >      descriptions that can be used as domain and range values of an
>  >      owl:equivalentClass statement. In OWL Lite **only class 
> identifiers and
>  >      property restrictions** are allowed as domain and range values. (?)
>  >
>  >      8.3 OWL Lite
>  >      ...
>  >      the subject of owl:equivalentClass triples be named classes and
>  >      the object of owl:equivalentClass triples be named classes,
>  >      restrictions, or subjects of owl:intersectionOf triples (?);
>  >      ...
>  >  ]
>  >
>  >  1) According to S&AS, the domain of owl:equivalentClass must be just
>  >     classID.
>  >
>  >  2) As to the range of owl:equivalentClass, class identifiers and
>  >     property restrictions are certainly allowed as range values. But how
>  >     about others allowed as range values? What's "the subjects of
>  >     owl:intersectionOf triples" mentioned in section 8.3?
>  >
>  >  It seems most likely to be anonymous classes defined as the
>  >  conjunctions of class identifiers and property restrictions.
>  >
>  >  It (The domain and range of owl:equivalentClass in OWL Lite) should
>  >  be explicitly and consistently specified.
>  >
> 
> In OWL Lite the domain of owl:equivalentClass must be a named class
> and the range must be be either a named class or a restriction..
> 
> We will delete the phrase "or subjects of owl:intersectionOf
> triples" from the first bullet of the list in Sec. 8.3 of Reference.
> 
>  >
>  >  3. RDF schema for OWL (Appendix B)
>  >
>  >  1) "rdf:resource" is a typo error as I mentioned before. It should be
>  >     "rdfs:Resource".
> 
> "rdf:resource is written with a lowercase in constructions like:
> 
> <rdf:Property rdf:ID="backwardCompatibleWith">
>     <rdfs:label>backwardCompatibleWith</rdfs:label>
>     <rdfs:domain rdf:resource="#Ontology"/>
>     <rdfs:range rdf:resource="#Ontology"/>
> </rdf:Property>
> 
> It is in the RDF namespace, so it should really be "rdf:"
> 
> 
>  >  2) The definition of owl:Thing and owl:Nothing
>  >
>  >  <Class rdf:ID="Thing">
>  >    <rdfs:label>Thing</rdfs:label>
>  >      <unionOf rdf:parseType="Collection">
>  >       <Class rdf:about="#Nothing"/>
>  >       <Class>
>  >         <complementOf rdf:resource="#Nothing"/>
>  >       </Class>
>  >     </unionOf>
>  >   </Class>
>  >
>  >  <Class rdf:ID="Nothing">
>  >    <rdfs:label>Nothing</rdfs:label>
>  >    <complementOf rdf:resource="#Thing"/>
>  >  </Class>
>  >
>  >  I suggest the axiom for owl:Thing be simplified as follows:
>  >   <Class rdf:ID="Thing">
>  >    <rdfs:label>Thing</rdfs:label>
>  >  </Class>
>  >
>  >  Is there any lose of meaning?
> 
> We think so. The class axiom for owl:Thing defines its class extension
> to be the extension of owl:Nothing plus its complement, which means all
> individuals in the universe of discourse. owl:Nothing is its complement,
> so its class extension is the empty set.
> 
>  >
>  >  I note owl:Nothing is not included in OWL Lite. [A note in section
>  >  3.1 Class descriptions].
>  >
>  >  Including owl:Nothing in OWL Lite will bring any harmness to OWL Lite ?
> 
> This comment will be answered in the context of your comments on OWL
> S&AS, see Peter Patel-Schneider's message:
> http://lists.w3.org/Archives/Public/public-webont-comments/2003Apr/0043.html
> 
>  >
>  >  4. The rdfs:range of owl:imports
>  >
>  >  In Appendix C (OWL Quick Reference), the rdfs:range of owl:imports is
>  >  missing. It should be owl:Ontology (according to Appendix B).
>  >
> 
> Thanks for spotting this. We will make the appropriate editorial change
> to Appendix C.
> 
> 
>  >
>  >  Yuzhong Qu
> 
> 
> Please can you reply to this message on the public-webont-comments@w3.org
> list, indicating whether we should be giving further consideration to your
> comment or whether these pointers have adequately clarified the situation.
> 
> Thanks again very much for your comments.
> 
> Regards, Guus Schreiber
> 
> -- 
> NOTE: new affiliation per April 1, 2003
> 
> Free University Amsterdam, Computer Science
> De Boelelaan 1081a, 1081 HV Amsterdam, The Netherlands
> Tel: +31 20 444 7739/7718
> E-mail: schreiber@cs.vu.nl
> Home page: http://www.cs.vu.nl/~guus/ [under construction]
> 
> 
> 
Received on Friday, 25 April 2003 08:28:22 GMT

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