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Re: Klyne Contexts: 3. Statements sets in RDF

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>
Message-ID: <87ae9gyv7s.fsf@astral.paranormal.se>
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

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