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Re: more about dereference (notes from MIT post F2F2-day-1)

From: Richard Cyganiak <richard@cyganiak.de>
Date: Thu, 13 Oct 2011 12:16:33 +0100
Cc: public-rdf-wg <public-rdf-wg@w3.org>
Message-Id: <99E4A7C0-3E0A-4FB7-AA98-C4C256A23ECB@cyganiak.de>
To: Sandro Hawke <sandro@w3.org>
On 12 Oct 2011, at 22:04, Sandro Hawke wrote:
> 1. If a system successfully dereferences URL "L" and obtains a
> representation of an RDF graph, then <L> is a GraphContainer.  That
> is, "L" denotes a GraphContainer.  Logically, GraphContainer is
> disjoint from foaf:Person (I think!!) so a document that includes "<>
> a foaf:Person" is (by this proposal) logically inconsistent with it
> being served on the Web.

This seems a logical consequence from httpRange-14.

> 2. So, owl:Ontology heavily overlaps GraphContainer.  It might even be
> a subclass of it.  (Many OWL ontologies say "<> a owl:Ontology", where
> the <> will be resolved to the address the ontologies is fetched from,
> aka L.)

Well, sort of. They are orthogonal by definition, but overlap in practice because it can be useful to treat owl:Ontologies as graph containers.

> 3. Some GraphContainers, "SerialGraphContainers" are functions mapping
> from time to RDF Graphs.  We can talk about next & previous & current
> RDF Graphs in a SerialGraphContainer, but not about GraphContainers in
> general.  (cf facebook's api for fetching RDF data, which returns
> different RDF data depending on your credentials).

I don't understand that. If graph containers are mutable, then doesn't that already mean they are functions mapping from time to RDF graphs?

> 4. A ConstantGraphContainer always holds the same RDF Graph.  This can
> be used for when you want to attach a dereferenceable URL to a g-snap.
> You put it in a ConstantGraphContainer.

Seems reasonable.

Richard
Received on Thursday, 13 October 2011 11:17:05 GMT

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