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RE: SKOS comment: change of namespace (ISSUE-117)

From: Alistair Miles <alistair.miles@zoo.ox.ac.uk>
Date: Thu, 31 Jul 2008 18:34:34 +0100
To: "'Simon Spero'" <ses@unc.edu>
Cc: <public-swd-wg@w3.org>, <public-esw-thes@w3.org>
Message-ID: <004201c8f333$b2b3d230$181b7690$@miles@zoo.ox.ac.uk>

Hi Simon,

If you consider that the tradition thesaurus BT relationship is currently
modeled in SKOS not by any single property, but by two properties, both
skos:broader and skos:broaderTransitive, then I believe the current design
is commensurate with your point of view.

I.e. skos:broader models the asserted BT relationship,
skos:broaderTransitive represents BT relationships that are either asserted
or can be inferred via the transitive closure. 

Sorry I don't have time for more right now. This feature will be marked "at
risk" in the last call working draft, so we won't close the door just yet.
I'm off for a week, but I look forward to getting into this issue in more
detail when I get back. I especially want to revisit the justification for a
parent/ancestor property pair, independently of any discussion and confusion
around naming. 

Thanks for the very educated and interesting debate.

Kind regards,

Alistair. 

--
Alistair Miles
Senior Computing Officer
Image Bioinformatics Research Group
Department of Zoology
The Tinbergen Building
University of Oxford
South Parks Road
Oxford
OX1 3PS
United Kingdom
Web: http://purl.org/net/aliman
Email: alistair.miles@zoo.ox.ac.uk
Tel: +44 (0)1865 281993


> -----Original Message-----
> From: public-swd-wg-request@w3.org [mailto:public-swd-wg-
> request@w3.org] On Behalf Of Simon Spero
> Sent: 28 July 2008 20:27
> To: Alistair Miles
> Cc: Laurent LE MEUR; public-swd-wg@w3.org; public-esw-thes@w3.org
> Subject: Re: SKOS comment: change of namespace (ISSUE-117)
> 
> On Fri, Jul 25, 2008 at 8:00 AM, Alistair Miles
> <alistair.miles@zoo.ox.ac.uk> wrote:
> 
> 
> 
> 	The argument against sticking with the old namespace is that the
> semantics have changed significantly. I don't think that's necessarily
> true. The only
> 	change to the semantics of an existing element is the change of
> skos:broaderto not being transitive. However, all data I know of
> currently published
> 	fits perfectly well with the usage pattern that "skos:broader is
> used to assert a direct hierarchical link between two concepts" -- and
> hence is perfectly consistent with the new data model. If anyone can
> provide a counter-example I'd be very grateful.
> 
> 
> 
> http://lcsh.info/
> 
> 
> The Hierarchical Relationship: Broader Topics and Narrower Topics
> [...]
> A heading is normally linked to one immediately next to it in the
> subject heading hierarchy. Since the referenced headings are linked in
> turn to ther headings, reference for distant relationships are no
> longer made. References leading to two or more levels in a hierarchy
> reflect an obsolete practice.
> 
> Library of Congress Subject Headings (22nd edition) vol. 1, p. x
> 
> 
> This policy corresponded to the introduction of explicit BT and NT
> relationship designators, and is incrementally implemented. This
> instruction is only plausible because the BT relationship is transitive
> ("No matter what the level at which one enters the hierarchy, one can
> follow either the  BT or NTs to find the broadest or most specific
> headings" (ibid)
> 
> In current LCSH, we have separate, explicit assertions that:
> 
> 1: Technological innovations BT Inventions        (TI  BT I)
> 2: Inventions BT Creative ability in technology    (I BT CAIT)
> 3: Technological  innovations BT Creative ability in technology   (TI
> BT CAIT)
> 
> Under the tranditional meaning  of BT, assertion 3 is uncessary, due to
> the semantics of hierarchical relationships.  Under LC rules, which are
> semantic preserving, it is safe to remove this link.
> 
> Removing it, we have
> 
> TI BT I ,  I BT CAIT   |= TI BT I, I BT CAIT,  TI BT CAIT
> 
> Under the original, correct, skos  semantics, broader operates the same
> BT.
> 
> TI broader I,  I broader CAIT |= TI broader I, I broader CAIT, TI
> broader CAIT
> 
> Under the new semantics
> TI "broader" I, I "broader" CAIT |/= TI broader CAIT
> 
> The semantics of the new "broader" are *clearly* not the same as BT, or
> the correct broader.
> 
> IF you want to keep the same namspace, rename the new
> "broaderTransitive" relationship to "broader", and rename the new
> "broader" relationship to "directllyAssertedBroader".
> 
> The BT relationship is intrinsically hiearachical and thus transitive.
> 
> 
> 
Received on Thursday, 31 July 2008 17:35:18 GMT

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