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RE: OWL, XML-RDF and Imports

From: Sean Bechhofer <seanb@cs.man.ac.uk>
Date: Mon, 17 Feb 2003 10:48:18 +0000 (GMT Standard Time)
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
cc: WebOnt WG <www-webont-wg@w3.org>
Message-ID: <Pine.WNT.4.44.0302171047220.2056-100000@potato>


On Mon, 17 Feb 2003, Jeremy Carroll wrote:

>
> Sean's proposal is that we additionally need to repeat
> <p> rdf:type owl:ObejctProperty .
> in FileB.
>
> This suffers from the following defects:
> - does not fit the C #include or Java imports paradigm, where the type
> information is imported; hence presenting greater difficulty to
communicate
> and learn
> - not robust. The current design will flag as an undeclared property
error
> the case where the user forgot the imports statement, or misubderstood
the
> nested imports. Under seans proposal the definition of <p> gets lost
> silently (since <p> has to be declared locally).

I think I've perhaps conflated (at least) two issues in my earlier
email.  I'd (probably) be happy to live with a situation where I have
to infer the types of things -- for example above with the property
p. In this case, a tool can always inform the user of the assumptions
it is making. However, the issue of splitting expressions across
different ontologies still concerns me.

In my opinion, it makes things *much* cleaner if I can at least decode
the triples into some other data structure which is closer to the
abstract syntax before processing them. And in particular do this
"locally" within each ontology.

Peter's redefinition:

[[
DEFINITION:  An RDF/XML document is an OWL DL ontology if

1/ the RDF graph resulting from parsing it as an RDF/XML document forms
the
   translation of a single OWL ontology in the abstract syntax;

2/ all RDF/XML documents that it imports are also in OWL DL ontology form;

   and

3/ the imports closure of the document

   a/ does not use any URI reference as more than one of an ontology name,
      a classID, a datatypeID, an individualID, a datavaluedPropertyID, an
      individualvaluedPropertyID, or an annotationPropertyID; and

   b/ does not use any of the URI references from the RDF, RDFS, or OWL
      namespaces that are mentioned in the RDF or OWL semantics except for
      the OWL datatypes, the OWL built-in classes, and the OWL built-in
      annotation properties.
]]

would, I think, alleviate my concerns. The definition seems to be
silent regarding the requirement for everything to be typed,
though. Is this deliberate?

       Sean

-- 
Sean Bechhofer
seanb@cs.man.ac.uk
http://www.cs.man.ac.uk/~seanb
Received on Monday, 17 February 2003 05:49:06 GMT

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