- From: Nikita Ogievetsky <nogievet@cogx.com>
- Date: Thu, 18 Dec 2003 05:55:15 -0800
- To: 'Bernard Vatant' <bernard.vatant@mondeca.com>, "'Www-Rdf-Logic@W3. Org'" <www-rdf-logic@w3.org>
Hi Bernard, My guess is that something like this should fix your class definition: <owl:Class rdf:ID="BlueThing"> <owl:intersectionOf rdf:parseType="Collection"> <owl:Restriction> <owl:onProperty rdf:resource="#color" /> <owl:allValuesFrom rdf:resource="#ShadeOfBlue" /> </owl:Restriction> <owl:Restriction> <owl:onProperty rdf:resource="#color" /> <owl:cardinality rdf:datatype="&xsd;nonNegativeInteger">1</owl:cardinality> </owl:Restriction> </owl:intersectionOf> </owl:Class> --Nikita ! -----Original Message----- ! From: www-rdf-logic-request@w3.org [mailto:www-rdf-logic-request@w3.org] ! On Behalf Of Bernard Vatant ! Sent: Thursday, December 18, 2003 2:00 AM ! To: Bernard Vatant; Www-Rdf-Logic@W3. Org ! Subject: erratum ... RE: allValuesFrom and rdfs:domain ! ! ! ! Oops ... Please read below ! ! <owl:Class rdf:ID="InvisibleThing"> ! <owl:complementOf> ! <owl:Class rdf:about="#VisibleThing"/> ! </owl:complementOf> ! </owl:Class> ! ! instead of ! ! <owl:Class rdf:ID="InvisibleThing"> ! <owl:complementOf> ! <owl:Class rdf:about="#VisibleObject"/> ! </owl:complementOf> ! </owl:Class> ! ! Thanks ! ! Bernard Vatant ! Senior Consultant ! Knowledge Engineering ! Mondeca - www.mondeca.com ! bernard.vatant@mondeca.com ! ! ! > -----Message d'origine----- ! > De : www-rdf-logic-request@w3.org ! > [mailto:www-rdf-logic-request@w3.org]De la part de Bernard Vatant ! > Envoye : jeudi 18 decembre 2003 10:38 ! > A : Www-Rdf-Logic@W3. Org ! > Objet : owl:allValuesFrom and rdfs:domain ! > ! > ! > ! > ! > I need some help from experts in logic ... ! > ! > I've sent a few days ago a message about "TexasThings" example ! > in OWL Guide ! > (see below), where the interpretation of allValuesFrom seems wrong to ! me. ! > Without answer so far from there, I push the question here. ! > ! > Suppose I have the following - more enlightening to me at least ! > than Texas ! > Things :)) ! > ! > <owl:Class rdf:ID="BlueThing"> ! > <owl:equivalentClass> ! > <owl:Restriction> ! > <owl:onProperty rdf:resource="#color" /> ! > <owl:allValuesFrom rdf:resource="#ShadeOfBlue" /> ! > </owl:Restriction> ! > </owl:equivalentClass> ! > </owl:Class> ! > ! > <owl:ObjectProperty rdf:ID="color"> ! > <rdfs:domain rdf:resource="#VisibleThing"/> ! > </owl:ObjectProperty> ! > ! > What can be asserted between the classes BlueThing and VisibleThing ? ! > ! > Of course, if some BlueThing X has a value for "#color", then X is in ! the ! > domain of "#color". But using "allValuesFrom" means that some other ! > BlueThing Y may not have any value at all for this property. ! > How can this happen? Quite naturally, if Y is not a VisibleThing ! > one might ! > not be able to specify any value for its color. One knows somehow Y is a ! > BlueThing, without being able to specify any ShadeOfBlue. ! > ! > So a BlueThing is not necessarily a VisibleThing. ! > ! > There is more tricky. ! > ! > <owl:Class rdf:ID="InvisibleThing"> ! > <owl:complementOf> ! > <owl:Class rdf:about="#VisibleObject"/> ! > </owl:complementOf> ! > </owl:Class> ! > ! > Does the following triple hold? ! > ! > InvisibleThing rdfs:subClassOf BlueThing ! > ! > Sounds weird ... but I can't find any solid argument against it. ! > ! > Bernard ! > ! > Bernard Vatant ! > Senior Consultant ! > Knowledge Engineering ! > Mondeca - www.mondeca.com ! > bernard.vatant@mondeca.com ! > ! > ! > -----Message d'origine----- ! > Envoye : lundi 15 decembre 2003 19:21 ! > A : public-webont-comments@w3.org ! > Objet : TexasThings and owl:equivalentClass ! > ! > Seems to me that there is something wrong, or at least ! > misleading with the ! > example of "TexasThings" ! > http://www.w3.org/TR/owl-guide/#equivalentClass1 ! > ! > <owl:Class rdf:ID="TexasThings"> ! > <owl:equivalentClass> ! > <owl:Restriction> ! > <owl:onProperty rdf:resource="#locatedIn" /> ! > <owl:allValuesFrom rdf:resource="#TexasRegion" /> ! > </owl:Restriction> ! > </owl:equivalentClass> ! > </owl:Class> ! > ! > First it would certainly be better to have the singular ! > "TexasThing" rather ! > than plural "TexasThings" :) ! > ! > "TexasThings are exactly those things located in the Texas region ..." ! > ! > This is obviously wrong. There is an allValuesFrom, but not a ! > someValuesFrom here. As defined, it means : If TexasThings are located ! > somewhere, they are located in Texas region. ! > ! > An further on ! > ! > " ... The difference between using owl:equivalentClass here and using ! > rdfs:subClassOf is the difference between a necessary condition and a ! > necessary and sufficient condition. With subClassOf, things that are ! > located in Texas are not necessarily TexasThings. But, using ! > owl:equivalentClass, if something is located in Texas, then it must be ! in ! > the class of TexasThings." ! > ! > ... but not the other way round, unfortunately. ! > ! > In fact under this definition any thing located nowhere is a Texas ! Thing. ! > Thinking about it, maybe it makes sense after all. Nowhere is indeed in ! > Texas, and especially its middle ... :)) ! > ! > ! > ! !
Received on Thursday, 18 December 2003 08:55:47 UTC