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Re: DAML+RDFS: potentials for simplifications?

From: Dan Connolly <connolly@w3.org>
Date: Tue, 11 Dec 2001 12:37:17 -0600
Message-ID: <3C16525D.645635D1@w3.org>
To: Pat Hayes <phayes@ai.uwf.edu>
CC: Jeen Broekstra <jbroeks@cs.vu.nl>, www-rdf-logic@w3.org
Pat Hayes wrote:
> >On Thu, 29 Nov 2001 Joachim.Peer@unisg.ch wrote:
> >
> >>  You say, a result of the simplified syntax is, that a
> >>  processor would need a "set of conventions". Yes, but how
> >>  does this differ from the current situation?
> >
> >It doesn't, and I think we are touching upon the core here:
> >by using a set of conventions (RDF!) that seems likely to be
> >shared by a broader community we are increasing
> >interoperability. Possibly at the cost of not having the
> >most optimal model, but this is a typical result of a
> >compromise. You can't have your cake and eat it, too.
> >
> >>  Are you aware of any DAML interpreter which has no
> >>  hardcoded set of DAML specific instructions?


It's not a complete DAML+OIL reasoner... it
sometimes goes into an infinite loop and sometimes
fails to find all valid conclusions. But
it handles DAML+OIL vocabulary in lots
of practical applications.
(It didn't handle cardinality as of a while
ago, but somebody just contributed some math
built-ins, so it might be able to now.)

> >Yes. Any RDF parser for example. Or the RDF Schema query
> >engine that we are currently building. Any RDF or
> >RDFS-specific tooling in fact.
> I think this answer is disingenuous. Any RDF parser can parse
> DAML+OIL , but it parses it as RDF, not as DAML+OIL. In order to
> 'interpret' (which I take to mean, be able to draw valid conclusions
> from) the DAML+OIL, one needs to know more than just RDFS: one needs
> to know how the DAML+OIL syntax is encoded into RDF. For example, one
> needs to know that some of the RDF is asserted as part of a DAML
> assertion, but other pieces of RDF are assertions about the syntax of
> the DAML assertions.

Huh? what do you mean by that? The software I use
treats all the assertions the same, and works quite well.

The spec says in so many words:

  "A DAML+OIL knowledge base is a collection of RDF triples."
	-- http://www.daml.org/2001/03/reference.html

> >True. But the RDFS-aware application will still know that
> >there is a relation called UnionOf.
> Right, but that is false in DAML+OIL. There is no such relation: that
> 'relation' is part of the syntax. See Peter Patel-Schneider's recent
> postings to the joint committee and the subsequent discussions:
> http://www.daml.org/listarchive/joint-committee/0934.html

The way you write this suggests that it's a position that's
agreed by all the DAML+OIL contributors, Pat. Please
be more clear.

As far as I'm concerned, there is a ont:unionOf relation;
it holds between a class and a list of classes.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 11 December 2001 14:38:49 UTC

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