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Re: semantics status of RDF(S)

From: Deborah McGuinness <dlm@ksl.stanford.edu>
Date: Mon, 02 Apr 2001 09:27:04 -0700
Message-ID: <3AC8A858.5A4624D7@ksl.stanford.edu>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: fikes@ksl.stanford.edu, www-rdf-logic@w3.org
I can not speak for the formal W3C RDF(S)  committee but will relay the gist of a few personal
communications.
When Richard Fikes and I published our axiomatic semantics
(http://www.ksl.Stanford.EDU/people/dlm/daml-semantics/abstract-axiomatic-semantics.html), we
received interest from  RDF(S) authors in using our axioms as the basis for the RDF(S)
semantics.  It is the case as far as I know that no formal statement has been made stating that
our axiomatization (or any other axiomatization) is the officially blessed foundation for
RDF(S).
Richard and I are happy to submit our axiomatization as the starting point.
We also welcome constructive suggestions on the axiomatization in its evolution  in serving the
DAML and broader W3C communities.
I would like to support Richard's suggestion that we might focus our discussion of the need for
a firm semantic foundation for RDF(S) in the form of constructive criticism of existing
foundations such as our document.

Deborah McGuinness

"Peter F. Patel-Schneider" wrote:

> The axiomatization for RDF and RDF(S) is one avenue that could be used to
> provide a firm semantic foundation for RDF and RDF(S).  However, this
> axiomatization has (as yet) no status with respect to RDF and RDF(S).
> Therefore I feel completely justified in critisizing RDF and RDF(S) as
> lacking in semantic grounding.
>
> One desirable effect of criticism of RDF and RDF(S) as lacking in semantic
> grounding should be the adoption of formal semantics for RDF and RDF(S).
> RDF and RDF(S) currently exist without formal semantics.  Further, there is
> no indication in any official RDF or RDF(S) documents that the lack of a
> formal semantics was considered to be a problem when RDF and RDF(S) were
> developed.  I take this to mean that some people are satisfied with the
> current state of affairs.  If no one complains about the lack of a formal
> semantics then nothing will be done.
>
> It is at least a bit hopeful that there are some issues in the RDF Issue
> Tracking document having to do with the lack of a formal semantics for RDF
> and RDF(S).
>
> Peter
>
> From: Richard Fikes <fikes@KSL.Stanford.EDU>
> Subject: Re: semantics status of RDF(S)
> Date: Sun, 01 Apr 2001 20:43:11 -0700
>
> > > 1/ There are many places in the RDF and RDFS documents where vitally
> > > important statements about the semantics of RDF or RDFS are presented with
> > > no formal backup, and in a totally inadequate fashion.
> > >
> > > For example, in Section 2.3.2 of the RDFS Specification 1.0 there are two
> > > paragraphs that give conditions on rdfs:subClassOf.  As far as I can tell,
> > > this is the only place that attempts to provide a meaning for rdfs:subClassOf.
> > > However, these two paragraphs use terms that are not defined in RDF or RDFS
> > > (such as set - classes are not sets and thus the subset relationship is not
> > > meaningful on classes), are sloppy in their terminology (rfds:subClass
> > > vs. sub/superset vs. subclass), and make unenforceable pronouncements
> > > (there is nothing in RDF(S) to prevent someone from creating the triple
> > > {rdfs:subClassOf, foo, foo}).
> >
> > I am puzzled at this criticism of RDF(S).  It is not news that the RDF
> > and RDFS specs do not contain an adequate formalization and semantics.
> > However, as you know, as least one formalization of the semantics or RDF
> > and RDFS has been produced and is presented in the paper by Deborah
> > McGuinness and myself titled "An Axiomatic Semantics for RDF, RDF
> > Schema, and DAML+OIL"
> > (http://www.ksl.Stanford.EDU/people/dlm/daml-semantics/abstract-axiomatic-semantics.html).
> > There no doubt have been others.  Criticism of existing formalizations
> > of RDF and RDFS would seem more appropriate and productive rather than
> > simply criticizing the specs.
> >
> > Richard
> >

--
=======================
Deborah L. McGuinness
Associate Director and Senior Research Scientist
Knowledge Systems Laboratory
Stanford University
Stanford, CA 94305
dlm@ksl.stanford.edu
voice  650 723 9770
fax 650 725 5850
Received on Monday, 2 April 2001 12:27:13 GMT

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