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Re: Inferring Class Membership w/o OWL Full?

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Sat, 8 May 2004 03:44:19 +0100
Message-ID: <16540.18819.203536.947564@excalibur.cs.man.ac.uk>
To: Pat Hayes <phayes@ihmc.us>
Cc: Stephen Rhoads <rhoadsnyc@mac.com>, www-rdf-logic@w3.org

For those who didn't follow the debates on the webont mailing list, I
should perhaps draw your attention to the sad history of Pat's morbid
obsession with DLs. I had hoped that having recognised the problem [1]
(the first and hardest step) he would by now be well on the road to
recovery. Sadly, it would appear that this is not the case. In fact
this is not Pat's first relapse [2], so perhaps we shouldn't be
surprised.

Ian

[1] http://lists.w3.org/Archives/Public/www-webont-wg/2002Sep/0411.html
[2] http://lists.w3.org/Archives/Public/www-webont-wg/2002Dec/0092.html


On May 7, Pat Hayes writes:
> 
> >I realize that everyone is probably beat from that "Classes as 
> >Values" discussion in the SWBP, but ... no thoughts on this?
> >
> >Would it be unthinkable to create a subPropertyOf rdf:type?
> 
> Its explicitly forbidden in OWL-DL by edict of the DL police, but it 
> makes perfect semantic sense and could be done in OWL-Full. On the 
> other hand, why not just use rdf:type? What do you gain from the 
> explicit subpropertying?
> 
> If you thought to sneak past the DL syntax restrictions, forget it. 
> The DL police have already thought of all the tricks you could use 
> and blocked all the exits.
> 
> Pat
> 
> >Something like ...
> >
> ><owl:ObjectProperty rdf:ID="hasGenre">
> >    <rdfs:subPropertyOf rdf:resource="&rdf;type"/>
> ></owl:ObjectProperty>
> >
> ><ex:Song rdf:ID="PurpleHaze">
> >    <ex:hasGenre rdf:resource="&ex;ClassRockMusic"/>
> ></ex:Song>
> >
> >Thus, the Individual "PurpleHaze" is an instance of both Song and 
> >ClassicRockMusic.
> >
> >Note that the intent is state class membership, not to say that the 
> >"subject" of the Song is a concept denoted by a Class (as in the 
> >"Classes as Values" paper).
> >
> >--- Stephen
> >
> >
> >On Apr 24, 2004, at 4:50 PM, Stephen Rhoads wrote:
> >
> >>
> >>Folks,
> >>
> >>There are various parts of my (Media Publishing and Distribtuion) 
> >>ontology where I would like to avoid the requirement of "multiple 
> >>typing".  The objective here is to simplify the ontology and user 
> >>interfaces which employ it.
> >>
> >>A user of the ontology should be able to simply declare an 
> >>Individual to be a Song, Album, Movie, MovieSeries, 
> >>TelevisionProgram, TelevisionSeries, RadioProgram or RadioSeries. 
> >>Other important class membership should be inferred by property 
> >>values.  A TelevisionSeries, for example, could have 
> >>"hasSeriesType" of "SeasonalSeries" and thus be a member of that 
> >>Class.  A Movie could have "hasGenre" of "Drama" and thus be a 
> >>Drama.
> >>
> >>The problem is that I can't see how to model this without landing 
> >>in OWL Full.  Take the following example:
> >>
> >>A sample Class hierarchy:
> >>
> >>Music
> >>    ElectronicMusic
> >>    PopMusic
> >>    RockMusic
> >>       ClassicRockMusic
> >>       GlamRockMusic
> >>       GrungeRockMusic
> >>
> >>And sample Class description:
> >>
> >><owl:Class rdf:ID="ClassicRockMusic">
> >>    <rdfs:subClassOf rdf:resource="#RockMusic"/>
> >>    <owl:equivalentClass>
> >>       <owl:Restriction>
> >>          <owl:onProperty rdf:resource="#hasGenre"/>
> >>          <owl:hasValue rdf:resource="#ClassicRockMusic"/>
> >>       </owl:Restriction>
> >>    </owl:equivalentClass>
> >></owl:Class>
> >>
> >>In other words, if the Individual (a Song or Album) hasGenre 
> >>ClassicRockMusic, then it *is* ClassicRockMusic (or at least a 
> >>member of a Restriction Class with the same class extension).  But 
> >>(I think) this puts the ontology into OWL Full because 
> >>ClassicRockMusic is being treated as both a Class and an Individual 
> >>(I can confirm that Racer will not accept the ontology from Protege 
> >>because it is "not in OWL DL").
> >>
> >>Thoughts?  Solutions?
> >>
> >>--- Stephen
> 
> 
> -- 
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Received on Friday, 7 May 2004 20:44:42 UTC

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