W3C home > Mailing lists > Public > www-webont-wg@w3.org > February 2002

REQDOC:stating closed worlds

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Fri, 15 Feb 2002 01:19:05 -0500
Message-Id: <p05101434b892579666ef@[]>
To: Jeff Heflin <heflin@cse.lehigh.edu>
Cc: webont <www-webont-wg@w3.org>
>5) You believe the "Ability to state closed worlds" requirement is too
>strong. Once again, this was a requirement that a significant number of
>people think is essential. Obviously, we can't make a closed-world
>assumption, but the ability to infer negative information from the
>absence of positive information is useful. However, I understand your
>concern in that this is not a feature found in existing langauges and
>may be difficult to implement.
>ACTION: We will demote "Ability to state closed worlds" to an objective.
>If anyone wishes to argue for it remaining a requirement, please do so.

I would like to see it remain a requirement, in some form. This issue 
keeps coming up in almost all parts of the sem web discussions. I 
have argued vehemently for the basic logic to be monotonic and am 
glad that this view seems to be predominant, but I also recognize 
that if we just say this, and do not address the needs of those who 
see an overwhelming use case for closed-world reasoning, then webont 
will never get widely deployed. Therefore, even if this is seen as a 
hard problem (I don't think its all that hard to make something 
workable), we ought to keep it firmly in our sights.

Pat Hayes
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Received on Friday, 15 February 2002 01:19:05 UTC

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