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Re: Question: disjointness of classes and datatypes

From: David Allsopp <dallsopp@signal.qinetiq.com>
Date: Thu, 23 Aug 2001 13:55:59 +0100
Message-ID: <3B84FD5F.94611678@signal.qinetiq.com>
CC: www-rdf-logic@w3.org


Peter Crowther wrote:
> 
> > From: David Allsopp [mailto:dallsopp@signal.qinetiq.com]
> > However, this disjointness is not expressed in the language
> > specification of DAML+OIL
> > (http://www.daml.org/2001/03/daml+oil.daml) as
> > far as I can see.
> >
> > Is there a reason for this?
> 
> The language spec specifies the syntax of DAML, not its semantics.  In a
> couple of places you need to be able to specify that a class or a datatype
> could occur, so it's difficult to enforce the disjointness in the syntax.

Ah. I guess one would have to create a superclass of both Class and
Datatype. 

I was just curious as to why, for instance 
[Thing--complementOf-->Nothing]  is in the language spec, which looks
like semantic content to me, but not [Class--disjointWith-->Datatype],
that's all.

> If you want to find the formal basis, you'll need to look at one of the
> semantics docs: axiomatic or model-theoretic.  For example, check out the
> model-theoretic semantics at
> http://www.daml.org/2001/03/model-theoretic-semantics.html.  The key appears
> to be in the preliminary mappings to the two domains AD (abstract) and DD
> (datatype) plus the definitions of IC and IO.

OK, thanks.

David Allsopp
QinetiQ
UK

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Received on Thursday, 23 August 2001 08:56:21 GMT

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