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Re: Scope of blank nodes in TriG?

From: Richard Cyganiak <richard@cyganiak.de>
Date: Mon, 17 Oct 2011 14:29:57 +0100
Cc: Steve Harris <steve.harris@garlik.com>, William Waites <wwaites@tardis.ed.ac.uk>, public-rdf-wg@w3.org
Message-Id: <FF49B45A-EFA6-4258-A2A7-9718126EF474@cyganiak.de>
To: Ian Davis <Ian.Davis@talis.com>
On 14 Oct 2011, at 12:35, Ian Davis wrote:
> I think the TriG spec could be updated by the authors so blank nodes
> are scoped to the document rather than the graph. It just seems like a
> bug in the spec to me.

No, it's not a bug.

The original use case for TriG (this is years before SPARQL existed) was serializing collections of RDF documents in a single document. In that use case there can be no blank nodes shared between documents, so graph scope made sense and had the convenient side effect of simplifying serializer implementation.

In N-Quads, which is post-SPARQL, and considered serialization of RDF datasets as a use case, we deliberately left it unspecified.

> This WG probably ought to decide on the semantics of blank nodes
> appearing in multiple graphs in a dataset.

I believe we have an issue for this on the tracker.

Best,
Richard
Received on Monday, 17 October 2011 13:30:47 GMT

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