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Re: Comments on RDF Concepts and Abstract Data Model

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 21 Nov 2002 15:33:39 -0500 (EST)
Message-Id: <20021121.153339.69321251.pfps@research.bell-labs.com>
To: phayes@ai.uwf.edu
Cc: w3c-rdfcore-wg@w3.org

From: pat hayes <phayes@ai.uwf.edu>
Subject: Re: Comments on RDF Concepts and Abstract Data Model
Date: Thu, 21 Nov 2002 14:24:09 -0600

> >From: pat hayes <phayes@ai.uwf.edu>
> >Subject: Re: Comments on RDF Concepts and Abstract Data Model
> >Date: Wed, 20 Nov 2002 13:14:27 -0600
> >
> >>  >From: Jeremy Carroll <jjc@hpl.hp.com>
> >>  >Subject: Re: Comments on RDF Concepts and Abstract Data Model
> >>  >Date: Mon, 18 Nov 2002 15:59:12 +0100
> >>  >
> >>  >>
> >>  >>  Hi Peter
> >>  >>
> >>  >>  I am responding to some of your comment
> >>  >>
> >>  >> 
> >>http://lists.w3.org/Archives/Public/www-rdf-comments/2002OctDec/0053.html
> >>  >>
> >>  >>  in particular:
> >>  >>
> >>  >>  [[
> >>  >>  Major comment:
> >>  >>
> >>  >>  The RDF graph is syntax.  As such it makes no sense to define a notion
> >>  >>  of equality over literals, which are pieces of syntax.
> >>
> >>  Peter, why do you say it makes no sense? It makes perfect sense to
> >>  me. If syntax is character strings, then equality is defined by
> >>  string equality; if it is some other kind of structure, then equality
> >>  is defined by other means. But it is still meaningful.
> >
> >Sure, it is possible to produce an equality relationship on syntax, and one
> >can do so without producing contradictions, but what has one achieved?
> 
> Call it 'identity' if you like to avoid the potential confusions with 
> equality in the language (though I havnt seen much evidence of that 
> confusion in practice). BUt heres an example of the need to get this 
> clear: what does it mean to be the same bnode? Its easy to slip past 
> the need to be clear on this, and this has caused large amounts of 
> confusion already. Purely syntactic confusion, but confusion all the 
> same.
> 
> Pat

Oh, yes, I agree that this is an area where a clear definition is needed.
However, this has nothing to do with literal equality, being much more akin
to whether two tokens in the syntax of a programming language refer to the
same variable.

peter
Received on Thursday, 21 November 2002 15:33:53 EST

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