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Re: ISSUE: DAML+OIL semantics is too weak

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 16 May 2002 19:15:03 -0400
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org
Message-Id: <20020516191503B.pfps@research.bell-labs.com>
From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: ISSUE: DAML+OIL semantics is too weak
Date: Thu, 16 May 2002 18:05:40 -0400

> At 2:45 PM -0400 5/16/02, Peter F. Patel-Schneider wrote:
> >TITLE:       DAML+OIL semantics is too weak
> >DESCRIPTION: DAML+OIL semantics (both the model theory and the
> >	     axiomatization) are too weak.  For example, it does not allow
> >	     the inference of membership in any restrictions that are not
> >	     present in the knowledge base, even though many of these are
> >	     desirable consequences.   For example, if John is an instance
> >	     of both Person and Employee, DAML+OIL does not sanction the
> >	     conclusion that John is an instance of an intersection of
> >	     Person and Employee.
> >RAISED BY:   Peter F. Patel-Schneider
> >REFERENCE:   too numerous to find a definitive reference
> Peter - is this meant to replace Issue 5.3 which you already raised 
> and we opened?   The "too numerous" references you mention were, as 
> far as I can tell, emails that have been allowed as part of this 5.3 
> issue

It is related, but different.

>   If this is a separate issue, can you add some text so the untrained 
> reader (or obtuse WG chair) can figure out how we could separately 
> discuss and/or close these issues (e.g. could we resolve one and 
> leave the open for a future group?)

Well, suppose WebOnt fixed the layering issue, perhaps by using an approach
with explicit comprehension principles that did not have paradoxes.
(Remember, however, that there are several people who believe that this is
probably not possible, and there is no proponent for this approach.)  It
still would be possible to have a too-weak solution.  For example, Jos has
been producing log:implies stuff that are, in a sense, like the
comprehension principles.  As far as I can remember, every set of
implications that he has produced has been shown to be too weak, in the
sense that there are desirable consequences that do not follow from the

>   -JH

Received on Thursday, 16 May 2002 19:15:14 UTC

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