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Re: [Paper:] Logical Interpretations of RDFS - A CompatibilityGuide

From: Wolfram Conen <conen@gmx.de>
Date: Mon, 19 Nov 2001 16:57:18 +0100
Message-ID: <3BF92BDE.7CEC0DD6@gmx.de>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: www-rdf-interest@w3.org
Hello Peter!

"Peter F. Patel-Schneider" wrote:
> My view of this paper is that it introduces a translation of the new RDF(S)
> model theory into Horn rules with stratified negation and then complains
> about characteristics of the result.  But are these complaints about the
> new model theory or about the translation?

Neither (by the way: note that the translation of the RDF(S) model
theory into the eighteen datalog rules does not require stratification,
though). It suggests that it might be reasonable to complain about the
loss of expressivity due to the decision of the RDF Core WG with respect
to domain/range constraints (ie, allowing to deduce types).

> The axiomatization for RDF(S)
> (http://www.ksl.stanford.edu/people/dlm/daml-semantics/abstract-axiomatic-semantics.html)
> developed by Richard Fikes and Deborah McGuinness as part of the
> axiomatization of DAML+OIL deserves a look in this context.

Sure. From a DAML/OIL perspective, where it contributes to the
development of the spec (ie, has somewhat normative character), it is
certainly a very nice document. From the perspective of someone who
wants to understand what is intended by the existing RDFS spec (CR
admittedly), it's does not seem to be so, because it does not try to
justify the taken design decision by referring to the RDFS spec. And the
domain/range case may be considered as a good example that the spec(s)
leaves room for interpretation (and thus, justifying decision seem to be
a good idea). That was precisely what we tried in summer 2000, based on
the even older approach of Antoine in his RDF tutorial: to give a
justifiable datalog "axiomatization" - if you look into last years
document, you'll see that we cite the spec intensively for this matter.

> Peter F. Patel-Schneider
> Bell Labs Research
> PS:  Calling the interpretation you developed as the ``old interpretation''
> and the new model theory as the ``new interpretation'' is unnecessary and
> prejudicial.  It implies that your interpretation has some sort of official
> status.

No, it certainly has no official status. It was addressed to the RDF
community (when we wrote it in summer 2000), it was the first more or
less complete approach to interpret the RDFS specs from a more formal
perspective, it induced quite a bit of discussion
for some samples ) and it maybe even have influenced some people in
their work. So, when we mean "old interpretation" this is strictly
intended as an abbreviation for OUR "old interpretation" (though there
had not been a lot of complaining about its way to interpret the spec)
-- the reason is simply that the paper was titled "A logical
interpretation of RDF". Sorry if you got the impression of claiming an
status, that was not our intention. 

> From: Wolfram Conen <conen@gmx.de>
> Subject: [Paper:] Logical Interpretations of RDFS - A Compatibility Guide
> Date: Thu, 15 Nov 2001 16:36:30 +0100
> > Dear RDF/RDFS interest email list readers,
> >
> > those of you who liked our old "Logical Interpretation of RDF" paper and
> > who want to explore the relation between the old interpretation and the
> > recent RDF Core WG work (decisions/Model Theory draft) might be
> > interested in our recent working paper (details see below).
> >
> > Title: Logical Interpretations of RDFS - A Compatibility Guide
> >
> > Location: http://nestroy.wi-inf.uni-essen.de/rdf/new_interpretation
> >
> > Those of you who haven't read the old paper may still profit from the
> > new one (hopefully). To allow for a more informed download decision, we
> > include the abstract and a brief structural overview below.
> >
> > We would be happy about your feedback (rdf@nestroy.wi-inf.uni-essen.de).
> >
> > Thanks for your kind consideration,
> >        Wolfram Conen & Reinhold Klapsing
> >
> >
> >
> > WORKING PAPER:   Logical Interpretations of RDFS - A Compatibility Guide
> > VERSION: 1.0
> >
> > This paper compares the semantics (or stated more precisely: an
> > interpretation of the intended semantics) of RDF and RDFS (as previously
> > captured in [1]) with the semantics defined by the new upcoming RDF
> > Model Theory [2]. While the RDF Model Theory Draft (MT) relies on set
> > theory, we interpret the MT utilizing a horn subset of first order
> > logic. On one hand, this may facilitate comprehensibility, on the other
> > hand it may lead more directly to verifiable implementations. The
> > comparison clearly demonstrates the differences between both
> > interpretations and discusses some consequence of the non-backward
> > compatible treatment of range/domain properties. It may thus help active
> > developers to understand the consequences of the changes for existing
> > RDF schemata and to adapt their RDF/RDFS applications accordingly where
> > possible.
> >
> >
> >
> > Sec. 1: Outlines the basic terminology (facts+deductive rules+integrity
> > constraints, Datalog).
> >
> > Sec. 2: Reviews the horn rules and facts of the old interpretation (of
> > the RDFS candidate recommendation)
> >
> > Sec. 3: Gives a new interpretation along the lines of the Model Theory,
> > again using horn rules (discusses also how some results of the Model
> > Theory can be proven within the Datalog/LFP framework we used
> > straightforwardly)
> >
> > Sec. 4: Compares the interpretations, points out the differences and
> > discusses some of the potential problems related to the changes of the
> > interpretation of range/domain constraints (Developer's beware! ;)
> >
> > REFS:
> >
> > [1] http://nestroy.wi-inf.uni-essen.de/rdf/logical_interpretation/
> >
> > [2] RDF Model Theory, Editor's Draft as accessed on November 5th, 2001.
> > A postcript version of the referenced version is available at
> > http://nestroy.wi-inf.uni-essen.de/rdf/new_interpretation/working-draft-mt-retrived-05-11-2001-12:00-GMT.ps
> > (The version has been retrieved from
> > http://www.coginst.uwf.edu/users/phayes/w3-rdf-mt-current-draft.html.)
> >
Received on Monday, 19 November 2001 10:57:50 GMT

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