- From: Ian Horrocks <horrocks@cs.man.ac.uk>
- Date: Tue, 11 May 2004 21:37:20 +0100
- To: Pat Hayes <phayes@ihmc.us>
- Cc: Stephen Rhoads <rhoadsnyc@mac.com>, www-rdf-logic@w3.org
On May 7, Pat Hayes writes: > > >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 > > Perhaps also not uncharacteristically, Ian manages to simultaneously > be insulting, offensively ad-hominem and to mislead the unwary > reader. The acknowledgement in [1] was to a completely unrelated > misunderstanding arising in part from my reaction to an extended > series of memoranda claiming to show that (what is now called) > OWL-Full was impossible, by a specious reference to the set-theoretic > paradoxes, but also in part, I concede, from my own ignorance of DL > metatheory at that time. The opinions I expressed in [2] are > unrelated to [1] , are not a 'relapse' - to acknowledge that DLs are > a subset of FOL is not to endorse the basing of the entire SW effort > on that subset - and I still hold them, and will continue to hold > them. > > I won't react to such jibes in future, but the record should be set straight. Strangely enough, that is exactly what I told myself when I read your initial email. The point I was trying to make with my [witty banter|vile character assassination]* is that, amusing though your ritual DL bashing is, it obscures the fact that the restriction being discussed here, i.e., not being able to create a subPropertyOf rdf:type, is nothing to do with DLs per se, but is required in order to keep the language inside what I think we agreed to call "conventional" FOL. In fact separating the syntax of the language from the domain of discourse is fundamental to most logics. Ian * delete as appropriate > > Pat > > > > >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 > >> > >> > >> -- > >> --------------------------------------------------------------------- > >> IHMC (850)434 8903 or (650)494 3973 home > >> 40 South Alcaniz St. (850)202 4416 office > >> Pensacola (850)202 4440 fax > >> FL 32501 (850)291 0667 cell > >> phayes@ihmc.us http://www.ihmc.us/users/phayes > >> > > > -- > --------------------------------------------------------------------- > IHMC (850)434 8903 or (650)494 3973 home > 40 South Alcaniz St. (850)202 4416 office > Pensacola (850)202 4440 fax > FL 32501 (850)291 0667 cell > phayes@ihmc.us http://www.ihmc.us/users/phayes >
Received on Tuesday, 11 May 2004 14:37:59 UTC