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RE: DTTF: summary (gasp!)

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 24 May 2002 12:44:55 +0100
To: "Jonathan Borden" <jonathan@openhealth.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <www-webont-wg@w3.org>
Message-ID: <JAEBJCLMIFLKLOJGMELDEEAICEAA.jjc@hplb.hpl.hp.com>

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 Friday, 24 May 2002 07:45:25 GMT

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