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Re: why I don't like named graph IRIs in the DATASET proposal

From: Ian Davis <ian.davis@talis.com>
Date: Wed, 5 Oct 2011 15:03:55 +0100
Message-ID: <CAAiX05G39+JfFRPwtnYBs09y50JVFJsjBzch+5PfXkRv5ch=uw@mail.gmail.com>
To: Richard Cyganiak <richard@cyganiak.de>
Cc: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>, "public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
On Wed, Oct 5, 2011 at 12:44 PM, Richard Cyganiak <richard@cyganiak.de>wrote:

> Ian,
>
> On 4 Oct 2011, at 22:47, Ian Davis wrote:
> >> Inference is defined over RDF graphs, not over collections of unasserted
> RDF graphs.
> >
> > While I agree with this statement, isn't it the case that most graph
> stores do inference over the collection of graphs in a dataset?
>
> Most graph stores don't do inference at all.
>

Of the ones that do can you list some that don't operate over the collection
of graphs as a single unit?



>
> > Given these two graphs in a single graph store and a schema that says
> ex:ancestor is transitive then I'm sure many inference enabled systems will
> answer true if asked whether :c is an ancestor of :a
> >
> > :G1 { :a ex:ancestor :b }
> >
> > :G2 { :b ex:ancestor :c }
> >
> > I'm pretty sure BigOWLIM does this, possibly others too.
>
> Like some other stores, BigOWLIM probably just by default places the union
> of all named graphs into the default graph. If it then does per-graph
> inference, then you get the effect you describe above when querying the
> default graph.
>

No, the default graph behaviour is configurable in BigOWLIM I believe.
However I think that behaviour isn't really relevant to whether inference is
done on a per graph basis or over a collection of graphs.

-- 
Ian Davis, Chief Technology Officer, Talis Group Ltd.
http://www.talis.com/ | Registered in England and Wales as 5382297
Received on Wednesday, 5 October 2011 14:04:26 GMT

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