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Re: NAF and NEG [was: LP Semantics (non-monotonicity) in Usage Scenarios?]

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Mon, 29 Aug 2005 11:26:03 -0400
To: Sandro Hawke <sandro@w3.org>
Cc: "Gerd Wagner" <wagnerg@tu-cottbus.de>, public-rule-workshop-discuss@w3.org, analyti@ics.forth.gr, "'Carlos Viegas Damasio'" <cd@di.fct.unl.pt>, antoniou@ics.forth.gr
Message-Id: <20050829152604.220B5CB5D3@kiferserv.kiferhome.com>

> > Yes, it is  a weaker kind of negation. My point is that it doesn't use NAF
> > and is suitable for cases like the pharmacy example in the charter where
> > you might not want to jump to conclusions.
> But the use case requires coming to life-and-death conclusions based
> on accessing only parts of the KB, which seems to require
> monotonicity.  Maybe there can be two kinds of conclusions - strong
> and weak/defeasible - drawn by two overlapping languages?  So you
> might come a stronge conclusions (these two drugs are safe together)
> or you might come a weak conclusion (there is no evidence so far that
> there is any harmful interaction between these drugs).  This is like
> having NEG and NAF, but any conclusions coming from NAF have to remain
> tainted by weakness.  (I'm sure this is all obvious and simple stuff
> to some of you; please bear with me and others and we learn how to put
> it together.)

Yes, this is precisely what I said. The weak classical negation does the
trick here; it is monotonic (it is what is called NEG in RuleML).

Received on Monday, 29 August 2005 15:26:29 UTC

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