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Re: Non-monotonic

From: Andrei Lopatenko <lopatenko@inf.unibz.it>
Date: Tue, 18 Nov 2003 10:57:59 +0100
Message-ID: <3FB9ED27.8020601@inf.unibz.it>
To: Drew McDermott <drew.mcdermott@yale.edu>
Cc: sean@smo.uhi.ac.uk, adrianw@snet.net, minsu@etri.re.kr, www-rdf-rules@w3.org, www-rdf-interest@w3.org

> However, I tend to agree with you.  Closed-world assumptions work
> quite well in practice and are well understood.  It's the purely
> monotonic case that's difficult. 

Usually  CW works well and is well understood in simple cases like 
relational databases.
If we have, for example, a disjunctive information then we need EGCW by 
Minker etc what makes reasoning more sophisticated.
Computational complexity of CW reasoning is also usually higher then OWA 
like PTIME problem  for OWA -> coNP for CWA, coNP ->EXPTIME. Change of 
computation complexity regions would mean a lot for Semantic Web, 
expected to deal with a huge amount of information, as far as I understand
So, probably, CW should be applied with a great care and only when it is 
really necessary

Another case is closed domain assumption (CDA). it makes computational 
complexity bound lower and lookes quite sound for some web applications.
Andrei Lopatenko


Received on Tuesday, 18 November 2003 04:53:39 UTC

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