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Re: nodes and node labels [was New document: revised version for WG review]

From: Dan Connolly <connolly@w3.org>
Date: 29 Jul 2002 15:50:46 -0500
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
Message-Id: <1027975847.21237.1479.camel@dirk>

On Mon, 2002-07-29 at 15:45, Jeremy Carroll wrote:
> 
> 
> I wanted to draw the WG attention, particularly Pat, to a mathematical issue
> with the graph syntax.
> 
> I do not believe that this has any substantive content, but is merely
> aesthetic!
> 
> 
> In the very first version of the model theory, the RDF graph was described
> as having nodes some of which had labels, and the labels were URI refs or
> strings.
> 
> In the most recent version, some of the nodes are URI refs and some of the
> nodes are strings (and none of the nodes are labelled).
> 
> In the new document draft, we have reverted to the earlier version using
> explicit node labels.
> 
> The motivations for this include:
> - tidying a graph is an explicit operation rather than implicit by
> mathematical construction
> - it easier to modify the exact tidyness specification (if the WG changes
> its mind about whether literals are tidy or not - uriref nodes don't seem in
> doubt).
> - implementations will almost all use nodes with explicit labels.
> 
> 
> The first point is the decisive one. From a mathematical point of view Pat's
> latest model theory treatment in which the URI refs and strings *are* the
> nodes is extremely elegant. Tidiness just falls out and no text needs to be
> spent on it.

Indeed.

(deep sigh of relief)

> However, in practice any implementor needs to be aware of tidiness as an
> operation which has to be coded,

???

> and any user needs some understanding of
> tidiness.

??????

I disagree.

Care to elaborate?

> Thus, I felt that Pat's earlier treatment, while a little more
> clunky, is clearer for our intended audience: implementators, users, web
> architects - rather than mathematicians.

I disagree.

> Although I raise this issue now, I would hope that any debate, if debate is
> needed, can be postponed until after the first WD. I don't think this is a
> crucial issue either way.
> 
> Jeremy
> 
> 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
see you in Montreal in August at Extreme Markup 2002?
Received on Monday, 29 July 2002 16:51:24 EDT

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