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RE: Klyne Contexts: 3. Statements sets in RDF

From: McBride, Brian <bwm@hplb.hpl.hp.com>
Date: Fri, 29 Dec 2000 17:05:02 -0000
Message-ID: <5E13A1874524D411A876006008CD059F2395B7@0-mail-1.hpl.hp.com>
To: "RDF Interest (E-mail)" <www-rdf-interest@w3.org>
> -----Original Message-----
> From: Jonas Liljegren [mailto:jonas@rit.se]
> Sent: 28 December 2000 23:36
> To: Graham Klyne
> Cc: RDF interest group; Wraf development
> Subject: Re: Klyne Contexts: 3. Statements sets in RDF
> 
> 
> 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]

The constraints on containers in m&s could be interpreted to
apply to the abstract data model - i.e. all bags must have
a contiguous set of members - in the abstract.  However,
a representation of the abstract model is perfectly free
to represent only a part of the abstract model and is
therefore free to represent only part of the bag and its
contents.  Under this interpretation, the above is valid.

Anything else seems bizarre.

> 
> 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]

That would be a valid RDF model but would violate ontology
cardinality constraints on the definition of bag.

Brian McBride
HPLabs
Received on Friday, 29 December 2000 12:05:10 GMT

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