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Re: car color defaults: a story about Scoped Negation As Failure/log:notIncludes

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 08 Jul 2005 07:18:24 -0400 (EDT)
Message-Id: <20050708.071824.31968921.pfps@research.bell-labs.com>
To: connolly@w3.org
Cc: public-rule-workshop-discuss@w3.org

From: Dan Connolly <connolly@w3.org>
Subject: Re: car color defaults: a story about Scoped Negation As Failure/log:notIncludes
Date: Thu, 07 Jul 2005 17:38:26 -0500

> On Thu, 2005-07-07 at 17:13 -0400, Peter F. Patel-Schneider wrote:
> > > Here's a sort of story we've written to explain and motivate
> > > log:notIncludes, aka Scoped Negation As Failure[1].
> > > 
> > > [[
> > > Because a formula is a finite size,
> > > [...]
> > > ]]
> > >  -- section "Implementing defaults and log:notIncludes" 
> > >   of part "Reaching out onto the Web"
> > >   of the Semantic Web Tutorial Using N3
> > >   http://www.w3.org/2000/10/swap/doc/Reach#Implementi
> > 
> > 
> > This isn't really the case in examples like:

[[An example of asking for all the conclusions that follow from a set of premises.]]

> Yes... cwm goes off into the weeds when you ask it to compute the
> log:conclusion of things like "fred's a person;
> every person has a father who is a person" but N3 semantics
> are intended to work with things like Euler that use
> backward chaining, so you're right to point out that
> this is an open issue in the design of N3.

And what then about log:conclusion?  It isn't going to work well with Euler, at
least not in the context of asking for all the conclusions that follow from a
set of premises.

[...]

> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E

Peter F. Patel-Schneider
Received on Friday, 8 July 2005 11:18:29 GMT

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