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Re: UPDATE: examples of layering

From: Dan Connolly <connolly@w3.org>
Date: 15 Feb 2002 12:18:11 -0600
To: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com>
Cc: webont <www-webont-wg@w3.org>
Message-Id: <1013797092.19337.51.camel@dirk>
On Fri, 2002-02-15 at 08:56, Peter F. Patel-Schneider wrote:
> 		Commentary on the Various Layering Possibilities
> 
> Here are some comments on the various layering possibilities.
> 
> 
> A) Here is a bit of syntax showing some potential differences between RDF
> syntax for OWL and an XML syntax for OWL.  I will use a fairly simple
> defined class. 
> 
> A1/ RDF Syntax (roughly DAML+OIL syntax):
> 
> <rdfs:Class rdf:ID="gop">
>   <owl:sameClassAs>

[... great big ugly thing, with a few bugs, elided...]

If I fix a few bugs, spell out the namespaces,
and use DAML+OIL's collection extension to RDF, I get
the following, which parses by machine:

<rdf:RDF xmlns:daml="http://www.daml.org/2001/03/daml+oil#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

    <rdf:Description rdf:about="#gop">
        <daml:intersectionOf rdf:parseType="daml:collection">
            <rdf:Description rdf:about="#Person"/>
            <rdf:Description>
                <daml:onProperty rdf:resource="#child"/>
                <daml:minCardinality>1</daml:minCardinality>
            </rdf:Description>
            <rdf:Description>
                <daml:onProperty rdf:resource="#child"/>
                <daml:toClass rdf:parseType="Resource">
                    <daml:unionOf rdf:parseType="daml:collection">
                        <rdf:Description rdf:about="#Doctor"/>
                        <rdf:Description rdf:about="#Laywer"/>
                    </daml:unionOf>
                </daml:toClass>
            </rdf:Description>
        </daml:intersectionOf>
    </rdf:Description>
</rdf:RDF>

OK, so that's not beautiful. But it works in a number of
implementations today: our swap/cwm tools, Jena, OILed,
etc.
Check it yourself:
  http://www.w3.org/RDF/Validator/

If the WG wants to spend its time re-hashing the syntactic
decisions that got us the syntax above, we could perhaps
do that. Our charter was drafted assuming a substantial
consensus around DAML+OIL's syntax. If that's not the case,
I expect the impact on our schedule would be
2 to 6 months. I'd have to go to the Semantic Web Coordination
Group with (a) support from most of the WG members that
they're happy to keep working that much longer and
(b) some argument that our market window will be open
that much longer. We could perhaps get a charter extension.

Is that what folks want to spend their time on?

Oh... by the way... about the ugliness...
I rarely use RDF/xml syntax as a user interface; we have
another language that we use as a user interface:

    <#gop>     ont:intersectionOf  (
        <#Person> 
         [
                 ont:onProperty <#child>;
                 ont:minCardinality "1" ]
         [
                 ont:onProperty <#child>;
                 ont:toClass  [
                     ont:unionOf  (
                    <#Doctor> 
                    <#Laywer>  ) ] ] ) .

for details, see http://www.w3.org/2000/10/swap/

I expect other folks will use nicer user interfaces than
ASCII text languages. OILed, protoge, RDFAuthor, that
sort of thing.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 15 February 2002 13:17:49 GMT

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