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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>
Dan,

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.

Jeff

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 GMT

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