I'm actually thinking of using some of standard W3C vocabularies on TechPresentations.org and I'm thinking of using ontology import like I do with http://www.techpresentations.org/Property:Homepage for, example.

But I was also thinking of defining my Properties and mapping them to W3Cs with ("same as" relations) just to have more flexibility in the future, so "Equivalent URI" seemed to be best solution in this case.

Since SMW instances only start to be part of overall Semantic Web, it'll be great if it was easy to provide data in the form that will make it easily participate in projects like LinkingOpenData ( http://esw.w3.org/topic/SweoIG/TaskForces/CommunityProjects/LinkingOpenData) without any additional tools to dump or otherwise export data. I'd appreciate any thoughts on this.


On Dec 21, 2007 7:45 AM, S Page <info@skierpage.com> wrote:
>> It's certainly an under-documented feature.

I put some documentation for this at

semediawiki-user@antispam.sergeychernyshev.com> wrote:

> Yaron, which RDF constructs do "Equivalent URI" and "Has URI" create?

I believe the special property "Equivalent URI" does nothing in the
current SMW 1.0 codebase except automatically assign Type:URL to its
value.  The code to handle it is commented out in Special:ExportRDF, and
 the only other user of it is Special:OntologyImport which is not
loaded by default and may not work.

It might still be useful to have a reserved property name for this
concept, but it seems this special property doesn't get exported at all,
e.g. http://ontoworld.org/wiki/Special:ExportRDF/Denny_Vrandecic doesn't
export the annotation
  [[equivalent URI:= http://vrandecic.de/nny]]
at all.

The only uses I see of this on ontoworld.org are a few user pages saying
there's an equivalent URI for them, the user's home page.  This usage is
slightly different than the usage Markus describes of associating a
*property* with a common meaning beyond the wiki.

(BTW, there is no property "Has URI".)

=S Page

Markus Krötzsch wrote:

> There is a reason for that ... we introduced this feature so that people could
> influence the RDF-export by adding alternative URIs about things in the wiki.
> This could be used, e.g., to align the RDF-export of two wikis that use some
> common terms and that do want to indicate in their export that the properties
> are actually the same as in the other wiki. So these properties are mostly
> used to tweak the RDF for further reuse -- if you do not understand this
> motivation, then you do not need that feature ;-).
> However, more recent versions of SMW introduced the "vocabulary import" which
> enables you to use a limited set of URIs directly in place of the basic wiki
> URIs. This feature is documented, and it has some better tool support since
> it just directly uses the new URI instead of just stating that it
> is "equivalent". We are still thinking about other features to allow custom
> URIs in the future, e.g. for special properties that are part of some SMW
> extension (they have always the same meaning, so they should use the same URI
> on all sites). Anyway, these are all Semantic Web issues that are relevant
> mostly for data exchange and reuse outside the wiki.

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