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Re: A use case for anon nodes - action from telecon

From: Graham Klyne <Graham.Klyne@Baltimore.com>
Date: Tue, 17 Jul 2001 18:55:02 +0100
Message-Id: <5.0.2.1.2.20010717184957.03bb1720@joy.songbird.com>
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: Aaron Swartz <me@aaronsw.com>, rdf core <w3c-rdfcore-wg@w3.org>
Brian,

You say (full message below):
>I'm not sure that standard FOL captures this.  FOL is built
>around a conceptual model where there can be many interpretations
>for statements in the FOL.  But that is not the situation we
>are in here.  We have one interpretation - its a mapping to
>the world out there.  Intuitively I feel that makes a difference.
>That makes naming special.

I don't think the problem is with FOL, but with the EC subset that RDF is 
presumed (by me, at least) to reflect.

In particular, the 'buyer advertisement' case that you relayed to us, which 
I have claimed is problematic to represent according to RDF M&S 1.0, I 
think probably can be captured adequately with FOL (allowing universal 
quantification as well as existential).  Roughly:

   For all X:
     ( X satisfies some conditions ) =>
       (some buyer wishes to purchase X)

#g
--

At 10:30 AM 7/17/01 +0100, Brian McBride wrote:
>Aaron,
>
>The thing to bear in mind about this submission is that these
>were not my words.  They were the words (with some HP specific
>stuff removed) of my colleagues who are using RDF in the manner
>described.  This input is from real developers.
>
>Aaron Swartz wrote:
> >
> > On Monday, July 16, 2001, at 02:23  PM, Brian McBride wrote:
> >
> > > (1) In the seller advert it would appear that the seller is
> > > only advertising a
> > > single specific (but under-specified) service, #anon12345 or
> > > whatever, which
> > > would be hard to distinguish from an actual service instance
> > > like #service42.
> >
> > Why would you want to distinguish between the two?
>
>I think the idea here is that there will be URI's
>denoting specific services.  My colleagues are
>interpretting a node with a URI to be denoting
>such a service.  It would be wrong to match a different
>service.
>
>When an anonymous node is specified, then no such constraint
>exists.  Thus a processor would process these two instances
>differently.
>
> > And I see
> > nothing about a URI that licenses you to assume that there is
> > only such thing.
>
>Oh we really do need this model theory don't we.  I tend to think
>of a URI as identifying one thing, and one thing only, but that way
>lies a philosphical debate on the nature of 'one'.  Shudder!
>
>
> >
> > > (2) Similarly in the buyer advert instead of describing a
> > > template, giving the
> > > service a URI would make it appear that I am looking for a
> > > specific service with
> > > that URI.
> >
> > Umm, aren't you? What's the difference? In both you're looking
> > for something with these properties.
>
>The difference is that when a URI is specified the assumption is
>that someone, somewhere has defined a 'well known' name for this
>service.
>
>The essence of this issue seems to involve the idea that the
>act of naming something in the internet is somehow, special.
>That if a processor is told that something has URI ISBN-12345
>or whatever, it had better not match that with anything that
>it does not 'know' is named ISBN-12345.  On the other hand,
>if a node is not named, then it can be matched with anything
>that matches its properties.
>
>I'm not sure that standard FOL captures this.  FOL is built
>around a conceptual model where there can be many interpretations
>for statements in the FOL.  But that is not the situation we
>are in here.  We have one interpretation - its a mapping to
>the world out there.  Intuitively I feel that makes a difference.
>That makes naming special.
>
>Brian

------------------------------------------------------------
Graham Klyne                    Baltimore Technologies
Strategic Research              Content Security Group
<Graham.Klyne@Baltimore.com>    <http://www.mimesweeper.com>
                                 <http://www.baltimore.com>
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Received on Tuesday, 17 July 2001 14:45:41 EDT

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