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Re: Why are RDF containers (rdf:Seq etc.) so little appreciated?

From: Axel Rauschmayer <axel@rauschma.de>
Date: Sun, 14 Feb 2010 11:34:23 +0100
Message-Id: <E378078D-9B9B-4363-B24B-0B15881EE0B7@rauschma.de>
Cc: Linked Data community <public-lod@w3.org>
To: Pat Hayes <phayes@ihmc.us>
> Im not sure what you  mean by 'stable identity',

It's a slightly (possibly unorthodox) viewpoint I take during RDF editing: With a container, you can say "I will edit the sequence at URI X" and be sure that X stays the same, no matter how you change the elements. With a collection, the "anchor" changes whenever one goes from 0 elements to 1 or more elements (or vice versa). Giving a collection a stable identity seems to have been one of the motivations behind skos:OrderedCollection.

> but the chief problem with containers is the fact that there is no way to 'close' them. If I say that FOO is a container and A, B and C are in it, there is no way to say that this is *all* that is in it. This makes them useless for encoding structures, eg OWL syntax. Collections' overcome this difficulty. So the collection notion is widely used to layer higher-level notations onto RDF, which is probably why toolkits have special provision for them.

I see the point, but it seems like one could achieve the same effect by adding an additional "nil" element (at the end) to a container.

> This does not stop you using the containers, of course. They are simple enough that you hardly need syntactic sugar, right?


True.

-- 
Axel.Rauschmayer@ifi.lmu.de
http://www.pst.ifi.lmu.de/~rauschma/
Received on Sunday, 14 February 2010 10:34:55 UTC

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