Hi Michael:
(moving this to LOD public as suggested)
General note: I am quite unhappy with a general movement in parts of the
LOD community to clash with the OWL world even when that is absolutely
unnecessary. It is just a bad engineering practice to break with
existing standards unless you can justify the side-effects. And this
stubborn "i don't care what the OWL specs says" pattern is silly, in
particular if the real motivation of many proponents of this approach is
that they don't want or cannot read the OWL specs.
As for owl:imports:
When importing an ontology by owl:imports, you commit to the whole
formal account of that ontology. If you just include an element from
that ontology by using it and hope that dereferencing will get the
relevant formal account in your model, you expose your model to
randomness - you don't know what subset of the formal account you will
get served. Ontology modularization is a pretty difficult task, and
people use various heuristics for deciding what to put in the subset
being served for an element. There is no guarantee that the fragment you
get contains everything that you need.
On the other hand - what is your pain with using RDFa in a way so that
the extracted RDF model is equivalent to the model from an RDF/XML or N3
serialization? Why this absolutely arbitrary "we LOD guys don't like
owl:import ( we don't like OWL anyway, you know?), so we simply omit it"
behavior?
It is just silly to break with established standards just for saving 1 -
2 triples.
Best
Martin
Michael Hausenblas wrote:
Martin,
As an aside: I think I proposed already once to not have this discussion in
a private circle of 'randomly' selected people but rather in the appropriate
lists (rdfa public or public-lod). However, if you prefer to continue here,
we continue here, FWIW.
In my opinion the owl:imports
stems from a time where people confused publishing on the Semantic Web with
firing up Protege and clicking around like wild. So, concluding, for me it
is not obvious to use owl:imports and I don't see *any* benefit from using
it. Not in RDF/XML and also not in RDFa ;)
you know that i sometimes appreciate your opinion ;-),
Yeah, same here :D
... but i think it is
pretty questionable to break with well-defined standards specifications
for just a matter of gut feeling and personal preference.
Ok, let me rephrase this. You, or whoever publishes RDFa can of course do
whatever she likes. Wanna use owl:imports? Fine. Don't wanna use it. Ok!
The point I was trying to make (not very successfully, though): from a
linked data perspective (and basically this is what Richard and I try to
achieve here; offering good practices for linked data *in* RDFa) the usage
of owl:imports is, how to put it, not encouraged.
So far I have not heard any convincing argument from you why one should use
it, but I'm happy and open to learn.
Cheers,
Michael
--
--------------------------------------------------------------
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen
e-mail: mh...@computer.org
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Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!
========================================================================
Webcast:
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http://tinyurl.com/semtech-hepp
Tool for registering your business:
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Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey
http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009
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