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Re: importing RDF and OWL

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 05 May 2008 19:01:34 -0400
To: Jos de Bruijn <debruijn@inf.unibz.it>
Cc: public-rif-wg@w3.org
Message-ID: <16707.1210028494@ubuhebe>


> I added a section [1] to the RDF and OWL compatibility document about 
> importing RDF/OWL and referring to the entailment regime.
>
> [1] http://www.w3.org/2005/rules/wiki/SWC#Importing_RDF_Graphs_in_RIF

Nice work.  Here are a few comments (that get especially muddy around
the promotion of contexts).  Sorry I didn't reply earlier.

* I can't parse the first sentence or two.  I think there a few words
  missing.

* There's no XML syntax given in BLD for import. What does the XML look
  like?  What roles names do you propose?

* I don't really like the document IRI's being used as Context IRIs.
  It's useful, but I see it raising some problems when you start to
  formalize the notion of Contexts.     Let's make up some other IRIs
  and link them back to the documents.  :-/    Something like
     http://www.w3.org/2008/rif-context#OWL_DL

* I'm a little concerned about your notion of promotion in a
  hierarchy of entailment regimes.  If we imagine a world with NAF, then
  promotion might be incorrect.  Maybe add a flag, so users have to
  explicitely "import with context = X" or "import with context >= X" ?

* What happens if OWL 2 includes a flag (as I hope/expect it will)
  indicating its own "Context"?  In that (hopefully common) case, should
  users leave out the context parameter (not possible in the syntax),
  should they provide a fully generic one, or should whatever they
  provide be ignored?  That is, is it an OVERRIDE for what the imported
  document claims to be, or a DEFAULT in case the imported document
  doesn't say?   I *think* it should be DEFAULT.

* I lean toward having just one Generic context.  Is OWL Full more like
  RDF or more like OWL?    I can't tell.   I can owl:import some OWL
  into some RDF, or some RDF into some OWL, right?

* Okay, I guess I'm general confused about whether and how promotion can
  work....     It sounds like I can't import some RDF triples and an OWL
  DL ontology at the same time....   I'll be forced to treat the DL
  ontology as OWL-Full, which is unimplementable.

* Any idea what construct you'd want to use for loading some OO-style
  XML?  Could we do that with Imports, too?

* ... I think maybe "Context" can be thought of as "Language".  You're
  loading some data/rules/knowledge, and naming the language it's
  written in, in case it's not properly labeled (as RDF data is not).

Again, overall it seems quite good, but I don't understand well enough
how contexts/language/etc is going to work in practice.   

      -- Sandro
Received on Monday, 5 May 2008 23:03:38 GMT

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