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aboutness and broader

From: Alistair Miles <alistair.miles@zoo.ox.ac.uk>
Date: Wed, 4 Jun 2008 10:14:27 +0100
To: <public-esw-thes@w3.org>
Message-ID: <004c01c8c623$63d493d0$2b7dbb70$@miles@zoo.ox.ac.uk>

Hi all,

I thought I'd write a quick comment on how "broader" interacts with the
notion of "aboutness", and how this could be captured formally.

A common view is that, if some concept B is broader than A, then if a
document D is "about" A, D is necessarily also "about" B.

(E.g. all documents "about" mammals are necessarily also "about" animals.)

To capture this view formally using RDF and OWL, we first need an RDF
property to represent our notion of "aboutness". For the sake of
illustration, let's use dc:subject.

We then express a property chain axiom. We say that the property chain
(dc:subject, skos:broader) is a sub-property of dc:subject.

Now, given this property chain axiom, the graph

<D> dc:subject <A>.
<A> skos:broader <B>.

entails

<D> dc:subject <B>.

Notice that the property chain axiom causes the dc:subject link to
"propagate" up the concept hierarchy until it reaches the top. I.e. the
graph

<D> dc:subject <A>.
<A> skos:broader <B>.
<B> skos:broader <C>.

entails

<D> dc:subject <B>, <C>. 

Notice also that this behaviour only depends on the property chain axiom. It
does not require that skos:broader be transitive.

Cheers,

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
Received on Wednesday, 4 June 2008 09:15:03 UTC

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