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Re: LANG: A proposal for the layering problem

From: Jeff Heflin <heflin@cse.lehigh.edu>
Date: Thu, 28 Mar 2002 15:42:43 -0500
Message-ID: <3CA38043.A986759F@cse.lehigh.edu>
To: Dan Connolly <connolly@w3.org>
CC: WebOnt <www-webont-wg@w3.org>

I don't believe your description about partial understanding, i.e., that
"the common syntax of RDF allows agents of various capabilities to
extract the same set of facts from a document." If the WebOnt language
(formerly known as OWL) provides additional semantics beyond RDFS, then
an RDFS agent cannot expect to extract the same facts from a WebOnt
document as a WebOnt agent would. Since WebOnt has additional semantics,
the WebOnt agent ought to be able to infer additional facts.

The fact that an RDF Schema agent can determine that daml:disjointWith
is a property or daml:UnambiguousProperty is class doesn't seem very
useful to me. If this is "partial understanding," then what's the point?

The Extensible Languages document you cite says "The resource defining a
namespace may be generic and allow definitions of the namespace in
varying present or future languages." Note that it doesn't say "in a
single language." RDFS Schema is one language for providing definitions
of a namespace. All I am proposing is that we provide definitions of the
namespace in a language other than RDF triples. This language can
coexist with RDF Schema and translation services can be written to allow
maximal understanding between RDFS and WebOnt agents.


Dan Connolly wrote:
> On Tue, 2002-03-26 at 10:22, Jeff Heflin wrote:
> > Dan,
> >
> > Can you describe what you don't like about my proposal?
> [...]
> > Let me try to refute the likely arguments in favor of building on top of
> > RDF schema:
> None of those is the critical one.
> The ciritical one is: partial understanding, as explained in [extlang].
> Briefly: the common syntax of RDF allows agents of various
> capabilities to extract the same set of facts from a document.
> If, in order to introduce properties and classes
> (such as disjointWith or UnambiguousProperty)
> we have to change our syntax for stating facts, we lose this.
> [extlang]
>  Web Architecture: Extensible Languages
>   W3C Note 10 Feb 1998
> This Version:
>   http://www.w3.org/TR/1998/NOTE-webarch-extlang-19980210
> Latest Version:
>   http://www.w3.org/TR/NOTE-webarch-extlang
> Authors:
>     Tim Berners-Lee <timbl@w3.org> W3C
>   Dan Connolly <connolly@w3.org> W3C
> esp the aircraft purchase order scenario
> http://www.w3.org/TR/1998/NOTE-webarch-extlang-19980210#Scenario
> --
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 28 March 2002 15:42:47 UTC

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