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Re: NAF v. SNAF - where is this being addressed?

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Wed, 29 Jun 2005 14:28:11 -0400
To: Jim Hendler <hendler@cs.umd.edu>
Cc: public-rule-workshop-discuss@w3.org
Message-Id: <20050629182812.A81A919E75F@kiferdesk.lmc.cs.sunysb.edu>


Yes, the charter must include this.  But I am not sure which charter is
being discussed. A particular document or in general?


> Mike - I didn't say that SNAF was controversial.  But it also cannot 
> be theoretical in the output of a Working Group (the context of my 
> email) -- an eventual charter has to include specific wording that 
> addresses this goal -- let me explain using examples from the Web 
> Ontology Group Charter that eventually led to OWL -- this charter is 
> in http://www.w3.org/2002/11/swv2/charters/WebOntologyCharter
> i. If there is a generally agree upon approach with a well-understood 
> semantics and a web-realizable syntax, then the charter should 
> specify this as a starting place
>       (for example, the Web Ont Charter stated that we must start from 
> ii.  If there isn't, then the specific goals of the mechanism to be 
> developed has to be stated (for example, the Web Ont charter 
> specified with respect to semantics that it must "clearly delineate 
> what is, and is not, entailed from any particular language construct 
> or combination thereof")
> So, in thinking about creating a working group, I am a bit confused 
> as to where we stand with this -- I know it is possible to do 
> something SNAF related, but now we must take it to the next level.
>   -JH
> p.s. Mike, let me use an example that might help you -- in the paper 
> you and Subrahmanian did, you proved all sorts of great things about 
> annotated logics.  However, if we were goign to do a standardization 
> of a particular annotated logic, we would have to be much more 
> specific and define a particular annotation set and corresponding 
> logic.  Your paper proves this could be done, and that it should be 
> done, but doesn't outline the specifics, so a charter would need to 
> limit the design space to the maximum degree (which is the goal of a 
> WG charter, and what makes them so danged hard to write)
> At 12:20 -0400 6/29/05, Michael Kifer wrote:
> >>  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.
> >
> >Jim,
> >Yes, SNAF is a generalization of NAF, and many people (including me) mean SNAF
> >(some prefer to call it scoped default negation) when they say NAF.
> >
> >
> >>    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)
> >
> >Some systems, like FLORA-2, inherently support SNAF. WRL was supposed to
> >have SNAF, but not in 1.0. This is work in progress. SWSL-Rules will also
> >have SNAF, but not in 1.0. (These two languages are actually quite close to
> >each other.)
> >
> >>    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
> >
> >Note that SNAF applies not only to data sets, but also to rulesets.
> >
> >>     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.
> >
> >SNAF is non-controversial, I think. It is a simple extension of NAF.
> >
> >
> >	--michael 
> >
> >>    -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
> -- 
> 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 18:28:20 UTC

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