- From: Jan Algermissen <jalgermissen@topicmapping.com>
- Date: Sun, 03 Apr 2005 21:47:36 +0200
- To: Dan Brickley <danbri@w3.org>
- CC: algermissen@acm.org, www-rdf-interest@w3.org
Dan Brickley wrote: >* Jan Algermissen <jalgermissen@topicmapping.com> [2005-04-03 21:14+0200] > > >>Hi, >> >>I want to use OWL class descriptions to define classes of documents but >>I can't find out, how to describe (for example) that an 'Article' has a >>sequence of sections. >> >>Here is an example: >> >>First I describe that 'Articles have exactly one dc:title and one >>dc:creator' >> >><owl:Class rdf:ID="Article"> >> <owl:equivalentClass> >> <owl:Class> >> <owl:intersectionOf rdf:parseType="Collection"> >> <owl:Restriction> >> <owl:onProperty rdf:resource="&dc;title" /> >> <owl:cardinality >> rdf:datatype="&xsd;nonNegativeInteger">1</owl:cardinality> >> </owl:Restriction> >> <owl:Restriction> >> <owl:onProperty rdf:resource="&dc;creator" /> >> <owl:cardinality >> rdf:datatype="&xsd;nonNegativeInteger">1</owl:cardinality> >> </owl:Restriction> >> </owl:intersectionOf> >> </owl:Class> >> </owl:equivalentClass> >></owl:Class> >> >>(That is the (a) way to do that I hope). >> >> >>I'd add other required or optional properties (such as teaser, copyright >>information, etc.) in the same way. >>I (think) I can say that an Article has 0...N sections with >>owl:minCardinality and owl:maxCardinality, but I want them to be ordered >>(of course). >>An instance of the Article class I have in mind would need to 'have' an >>rdf:Seq containing the sections, I think (correct?). Could anyone help me >>with the question of how I say that in OWL? >> >> > >A brief comment. I think the core issue here is two subtle senses of >'have'. The thing in the world, ie. the article itself, might have >certain things true of it. And then some specific RDF instance data >might carry RDF statements describing some or all of those things. OWL >talks in terms of constraints regarding things in the world, rather than >constraints on the content of RDF documents about those things. > Yes, I see what you mean (I think ;-) I have thought about that, too. Maybe I can clarify my position by saying that my sections are 'first-class objects'; that they have identity. Therefore I understand the relationship between the article and a section in the same way as a relationship between e.g. an employee and a department. IOW, I use the same understanding of 'data modeling' for concepts and their relationships as for documents (also just a concept) and their content elements (also just concepts). Jan >XML by >contrast is all about types of document (and in RDF/XML, about types >of description). So I think you need to know whether your rules are >to be rules about the properties of 'Articles' in the abstract, or about >the characteristics of specific RDF/XML descriptions of them. > >Hmm that's maybe a bit confusing. I'll have a think about how to >rephrase... > >hope it might help anyway, > >Dan > > > > >>Note: >> >>- I know that XML would be my friend here, but I do want to use RDF >>- I also do not want to use XML semantics (like the infoset RDF namespace) >>to express the desired content model >> >>Many! thanks in advance for any clarification of this issue. >> >> >>Jan >> >> >> >>-- >>Jan Algermissen >>Consultant & Programmer >>http://jalgermissen.com >> >> >> >> > > > -- Jan Algermissen Consultant & Programmer http://jalgermissen.com
Received on Sunday, 3 April 2005 19:47:42 UTC