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NAF v. SNAF - where is this being addressed?

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 29 Jun 2005 10:53:02 -0400
Message-Id: <p06200715bee8662ad500@[172.31.0.192]>
To: public-rule-workshop-discuss@w3.org
All, forgive me if I missed something since I wasn't able to attend 
the workshop.  My understanding from the workshop report, and from 
discussion with Tim BL and others afterwards, was that NAF wasn't 
going to make sense, but SNAF would -- that is, on the Web, if there 
is not a mechanism for defining the "KB" (graph) that a set of rules 
is applied to, there's not way to use a geenralized negation as 
failure -- i.e. I cannot say to the "whole web" that someone can be 
assumed to have two children unless it is shown they have a different 
number.  Instead, I need a way to designate the dataset that a rule 
like this is applied to.  SNAF, as I understand it, was the term 
being used to designate this.
  Yet, reading just about all the mail since the workshop, I haven't 
seen this referred to at all (and it's not really discussed in the 
WRL vs. SWRL or other threads currently being discussed in rdf-rules 
and sws-ig)
  Seems to me if I see your rule set includes a NAF-based rule, and 
you give me a conclusion to something, that if I don't know what 
graph/KB/DB that was applied to, then I have no way to know whether I 
can use your result in my application
   Seems to me also that this has a big effect on the charter, as I 
don't know if there is an agreed upon use of SNAF for the Web, and 
would need to be something the WG would be required to elucidate.
  -JH
p.s. Note that in datalog, there is always the assumption that the 
rules and a particular database can be linked - on the Web, that is 
not necessarily true.

-- 
Professor James Hendler			  Director
Joint Institute for Knowledge Discovery	 	  301-405-2696
UMIACS, Univ of Maryland			  301-314-9734 (Fax)
College Park, MD 20742			  http://www.cs.umd.edu/users/hendler
Received on Wednesday, 29 June 2005 14:53:23 GMT

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