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Re: rdf in atom





On 01/07/2008, at 5:58 PM, Story Henry wrote:

Nice work. I welcome the effort to find a mapping from atom to rdf.

There are two problems though:

(1) Rather than having an IETF document explain how to make explicit a mapping of every instance of the atom format to rdf it would be better to create an ontology for atom and specify an official GRDDL transform for it.

We weren't looking for a full mapping of Atom to an ontology, but rather a lightweight way to move statements around in Atom.

IMO, the problem with trying to define or use an Atom ontology has always been that most authors and extension writers don't have RDF in mind; while extracting semantics from the world around you is interesting, there also needs to be a way to shove them around with demonstrable intent, so that there isn't any ambiguity about what's happening.

WRT using GRDDL or other out-of-band mechanisms -- the overhead of processing GRDDL is IMO not acceptable in some cases, and furthermore, it's again not explicit/self-describing.

(2) I think the semantics of atom are wrong in the draft. It would have helped somewhat to consult on the work of the atom-owl [1] group before putting this spec together.

The key problem is the value of the subject:

[[
  <atom:entry>
   <atom:id>http://example.com/a</atom:id>
   <atom:title>Test</atom:title>
  </atom:entry>

  and the map above as a child of at:entrymap, the following triple
  would be implied;

<http://example.com/a> <http://purl.org/dc/elements/1.1/title> "Test" .
]]


By making the value of the subject be the resource identified by the id, you are going against what at least two independently built ontologies for atom consider to be the value of the subject of the entry.

That is only the default; see the subject attribute.

[...]

It cannot be therefore that you have correctly captured the semantics of the atom format.

That is not a goal for this effort.

Cheers,


--
Mark Nottingham     http://www.mnot.net/