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Re: aboutness and broader

From: Peter Ansell <ansell.peter@gmail.com>
Date: Wed, 4 Jun 2008 19:41:55 +1000
Message-ID: <a1be7e0e0806040241p7be72fb7s283ceb9ec86a8a1b@mail.gmail.com>
To: "Jonathan Chetwynd" <j.chetwynd@btinternet.com>
Cc: "Alistair Miles" <alistair.miles@zoo.ox.ac.uk>, public-esw-thes@w3.org

I presume that there is a difference between the categorisation aspect
where documents about children can be said at the "type" level to be
also "about" their parent types. Assuming relationships at the
concept/document property level goes further than the basic
concept/document organisation aspect of skos, IMO. I don't think SKOS
shouldn't reinvent the rigidity that OWL enforces if you take it
strictly.

Peter

2008/6/4 Jonathan Chetwynd <j.chetwynd@btinternet.com>:
> Alistair,
> as always with issues around logic, the reasoning isn't always apparent to
> the outsider...
> I'm not clear about your use of "necessarily", please can you expand
> briefly?
> ie what does "mammals have breasts" tell us about animals?
> or "carrots are orange" tell us about vegetables?
> other than some B can be D? but not necessarily?
> and how does that relate to "animals are motile" not telling us about
> mammals?
> ie all mammals are motile? is necessarily? though...
> cheers
> ~:"
> please excuse my ignorance in this field
>
> Jonathan Chetwynd
>
> j.chetwynd@btinternet.com
> http://www.openicon.org/
>
> +44 (0) 20 7978 1764
>
> On 4 Jun 2008, at 10:14, Alistair Miles wrote:
>
> 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 09:42:30 UTC

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