W3C home > Mailing lists > Public > www-rdf-logic@w3.org > April 2002

RE: DAML Level of Effort for FY03-FY05

From: Dan Brickley <danbri@w3.org>
Date: Tue, 23 Apr 2002 06:54:06 -0400 (EDT)
To: Didier VILLEVALOIS <dvillevalois@techmetrix.net>
cc: Jeff Heflin <heflin@cse.lehigh.edu>, Drew McDermott <drew.mcdermott@yale.edu>, <drager@bbn.com>, <www-rdf-logic@w3.org>
Message-ID: <Pine.LNX.4.30.0204230634190.5829-100000@tux.w3.org>
On Mon, 22 Apr 2002, Didier VILLEVALOIS wrote:

> Hello,
>
> Shouldn't RDF support something like daml:imports in its core ??
> daml:imports would be a subPropertyOf 'rdf:imports'.
> As rdf enables to speak about the same things in different places, it needs
> a such mechanism.

One problem with pushing this down into RDF's core is that the meaning
isn't clear, and (worse) that the clarification of the meaning isn't
something we can easily do with any of the formalisms currently being used
for RDF, DAML+OIL, WebOnt.

One reading might be akin to the XML Inclusions mechanism. Very low level.
See http://www.w3.org/TR/2002/CR-xinclude-20020221/
[[
Abstract
    This document specifies a processing model and syntax for general
    purpose inclusion.  Inclusion is accomplished by merging a
    number of XML information sets into a single composite Infoset.
    Specification of the XML documents (infosets) to be merged and
    control over the merging process is expressed in XML-friendly
    syntax (elements, attributes, URI references).
]]

I don't find much use for XML-level inclusion mechanisms in RDF content,
I guess because the imperative sense of "hey, you must go grab that XML
and include it here" seems at odds with the largely passive, descriptive,
propositional nature of RDF/DAML+OIL content.


Another version at a different level of abstraction would be that the
current document "in-some-sense-buys-into" the worldview, claims etc
(including associated axioms etc) of the referenced document. This is hard to get
right.

I don't see any particular reason why such mechanisms need to be defined
solely for ontologies/schemas, either.

This is an interesting problem though. But until we see a clear definition
of 'imports' that tells me what I'm doing when I say my doc imports
another, I'm not interested in deploying that property in my data. Too
risky! I'd also want to be able to import a frozen representation of a
namespace or ontology (eg. with sha1/md5 or XML signature).

All the while 'imports' isn't in the core of RDF, people can reasonably
claim they didn't know what it means, that it is just some utility
vocabulary. If we put it in the main specs, we'd need to be a lot clearer
on what conclusions 'imports' allows us to draw about a document and its
author/publisher.


Dan


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Received on Tuesday, 23 April 2002 07:51:52 GMT

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