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Re: DTTF: summary (gasp!)

From: Jonathan Borden <jonathan@openhealth.org>
Date: Tue, 28 May 2002 00:14:45 -0400
Message-ID: <027701c205fe$3411a980$0301a8c0@ne.client2.attbi.com>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <www-webont-wg@w3.org>
Jeremy,

thanks for this short and cogent explanation.

whether at the end of the day we accept the A-box/T-box distinction (or
whether OWL is incarnated as some type of DL or as a child of DL and
something else, or several other things ... hmmm) what your writing does
indicate to me at least, is that there is an accepted method for writing a
model theory for DL that might be applied to OWL. I take it that proceeding
in this direction would not be considered "new research".

On the other hand, the idea of merging DL with the RDF "classes as
instances" worldview seems appealing (and "classes as instances" is in our
requirements), so perhaps we can engage in a touch of research if this can
be done in a low risk fashion, and can be made to work on relatively short
order.

Thanks -- I've included a good chunk of this language in the most recent
summary.

Jonathan


>
> The T-Box is the description of the classes and properties used in an
> ontology or schema, the A-Box is the description of the objects in the
> domain of discourse.
>
> Thus rephrasing the very short summary, embedding these definitions of
> the A-Box and T-Box words comes to:
>
> All formally specified Description Logics separate the assertional
> descriptions of objects in the domain of discourse from the
> terminological descriptions of the classes and properties used within
> these assertional descriptions. RDFS does not make this separation. Thus
> the WebOnt WG has considered doing Description Logic without this
> separation and concluded that it is too difficult. Darkness is a bit
> that allows distinguishing: some (non-dark) parts of an RDF graph as
> following RDFS semantics, this will correspond to the assertional
> descriptions, from some parts of an RDF graph that correspond to the
> terminological descriptions, these will not follow the RDFS semantics.
>
> In particular the following implication that is valid under RDFS will
> not hold under OWL.
>
> eg:prop rdfs:subClassOf owl:Restriction .
> _:x rdf:type eg:prop .
>
> entails
>
> _:x rdf:type owl:Restriction .
>
>
> Jeremy
>
>
>
> Jeremy:
> > > Description Logic makes a distinction between the A-Box and
> > the T-Box;
> > > we have tried and failed to remove this distinction while not "doing
> > > research". We will use darkness to identify the T-Box; whereas A-Box
> > > semantics will extend RDFS semantics.
> > >
> >
> > Ok, can you give me some specific, relatively non-technical
> > language, that I
> > could incorporate into a message appropriate for RDFCore WG?
> > Or does RDFCore
> > need be concerned with this distinction (i.e. that's something we can
> > discuss amonst ourselves)?
> >
> > Jonathan
> >
> >
> >
>
>
Received on Tuesday, 28 May 2002 00:12:10 GMT

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