- From: <jos.deroo@agfa.com>
- Date: Tue, 5 Apr 2005 22:06:20 +0200
- To: 50263336@student.cityu.edu.hk
- Cc: Chris Purcell <cjp39@cam.ac.uk>, semantic-web@w3.org
> Oh my God.. i'd not make mistake again if it's in set.. :) > CEXT(S(#X)) = {<#A>} > CEXT(S(#Y)) = {<#A>,<#B>} > CEXT(S(#Z)) = {<#A>,<#C>} > i.e. > <#A> rdf:type <#X> , <#Y> , <#Z> . > <#B> rdf:type <#Y> . > <#C> rdf:type <#Z> . > => > <#X> rdfs:subClassOf <#Y> , <#Z> . > => > <#X> owl:intersectionOf (<#Y>,<#Z>) . > > I admit that this kind of inference requires a condition that the collection > of facts is complete. Otherwise the inference results may be ruined if a > fact like <#B> rdf:type <#X> is asserted. However, it is not a too bad > interpretation because the OWL interpretation still satisifies the RDF graph > above. One could say :X owl:oneOf ( :A ). :Y owl:oneOf ( :A :B ). :Z owl:oneOf ( :A :C ). and then :X rdfs:subClassOf :Y, :Z. easily follows, using such rules as { ?B has owl:oneOf ?Y. ?A has owl:oneOf ?X. ?Y :includes ?X } => { ?A rdfs:subClassOf ?B }. { } => { ?X :includes rdf:nil }. { ?S rdf:first ?A. ?X :item ?E. ?E has owl:equivalentClass ?A. ?S rdf:rest ?B. ?X :includes ?B } => { ?X :includes ?S }. { ?S rdf:first ?X } => { ?S :item ?X }. { ?S rdf:rest ?B. ?B :item ?X } => { ?S :item ?X }. At this moment, I can't find proof for :X owl:intersectionOf ( :Y :Z ). i.e. probably have to add some more owl-rules.. > In addition, my main concern is the use of the universal quantification and > the existential quantification. It is because N3 Rules cannot express the > inference described in the above example. My work of rules shows that N3 > Rules is very weak to model OWL restrictions, anyway. I hope to discuss or > to find out the use of the quantification facilities so that the rule-based > approach becomes more powerful as expected. You can have look at http://www.w3.org/2000/10/swap/doc/Rules and convince yourself that it can be easily done :) > :) > Jeremy -- Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Tuesday, 5 April 2005 20:06:45 UTC