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Thus sprach metadata

Seairth Jacobs gets it. RDF triples can be lossy when merged from their originally stated context.

More importantly, all of this leads me to the belief that 'triples' (subject, predicate, object) are not enough to make a semantic web of information, at least not outside of very restricted environments. To make the semantic web a reality, we need to start thinking in terms of 'quadruples' (source, subject, predicate, object).

Uche Ogbuji talked up quads for RDF years ago. Statement provenance is a major use case that future specification work needs to address. I think the reason the RDF specs missed this in the past is because many of us thought that reification would cover it (it doesn't), along with other stuff like quotation (nope). Oh well, maybe OWL can cover it off.

The XML dump format I came up with for RDF recently has an optional fourth member of the tuple called 'context'. Ditto for the RDF backed logging I'm prone to doing - it's not always enough to have a statement - sometimes you need a source for that statement.

May 23, 2004 01:45 AM


(May 23, 2004 10:06 AM #)

Jeremy Carroll and others have been working with a slightly different approach to the same ends - named graphs. Basically a graph has a URI so the provenance is directly available. I think the best current refs are these (from an rdf-interest post):

The current status quo of the trix work is described in

Beside of TriX, there is also a N3-like syntax for Named Graphs called TriG,

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» The Web is semantic, the Semantic Web is not from the iCite net development blog
Also relevant, see Seairth Jacobs' quadruples, not triples (via Bill de hÓra's Thus sprach metadata, which also has relevant comments). [Read More]

Tracked on May 23, 2004 08:32 PM