- From: Jonas Liljegren <jonas@rit.se>
- Date: 29 Dec 2000 00:36:23 +0100
- To: Graham Klyne <GK@Dial.pipex.com>
- Cc: RDF interest group <www-rdf-interest@w3.org>, Wraf development <rdf@uxn.nu>
Graham Klyne <GK@Dial.pipex.com> writes: > It seems to me that, given an RDF graph, I should be able to extract > an arbitrary subgraph (i.e. a subset of the statements) and still have > a valid RDF graph. The RDF approach to containers doesn't permit > this, because (I think) the following is not valid per RDF M&S: > > [Foo] --rdf:type--> [rdf:Bag] > [ ] --rdf:_1----> [Member1] > [ ] --rdf:_3----> [Member3] I say that it must be valid. I would even allow: [Foo] --rdf:type--> [rdf:Bag] [ ] --rdf:_1----> [Member1] [ ] --rdf:_1----> [OtherMember1] [ ] --rdf:_3----> [Member3] This because anyone can say anything about everything. > >In Wraf [2] I'm planning to store container members in a special way, > >optimized for compact storage and easy manipulation. With such > >optimizations, there is no need for another type of > >rdfs:ContainerMembershipProperty. > > I'd suggest that you are, in effect, implementing something slightly > different than that specified by RDF M&S. I want (need) to make the > required difference explicit in my model. Nobody can stop me if I feel like renumbering the properties of a bag. But it should be clear that the new statements is not the original ones. > >1. With special methods for conatiner handling, you will not have to > > bother about the present content. Wraf will give each container > > the dynamic property 'size', and methods for adding and quering the > > container without knowing each propertys number. > > This assumes that your implementation knows about all of the members. > I think that's a kind of closed-world view. No. The size statement has a source. Other sources can have another idea about the size of the container. The statement will belong to a model and that model will have data about the scope of the known world. > > [1] http://public.research.mimesweeper.com/RDF/RDFContexts.html > > [2] http://www.uxn.nu/wraf/ -- / Jonas Liljegren The Wraf project http://www.uxn.nu/wraf/ Sponsored by http://www.rit.se/
Received on Thursday, 28 December 2000 18:35:05 UTC