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RE: Exactly what does broader/narrower mean?

From: Stella Dextre Clarke <sdclarke@lukehouse.demon.co.uk>
Date: Mon, 19 Feb 2007 13:00:35 -0000
To: "'Richard Cyganiak'" <richard@cyganiak.de>, <public-esw-thes@w3.org>
Cc: 'Sören Auer' <auer@informatik.uni-leipzig.de>
Message-ID: <000c01c75425$f53f2db0$0300000a@DELL>

Richard,
I'm not sure SKOS prescribes in detail what conceptual relationships
qualify for broader/narrower.

If the vocabulary in question is an ontology, then there will be very
rigorous rules for each relationship it includes.

If the vocabulary in question is a thesaurus complying with ISO 2788 or
BS 8723-2, The rules are not quite so rigorous, but they exist
nonetheless. Broader/narrower relationships are permitted when:
(a) the concepts are generically related, for example plants/trees or
furniture/chairs;
(b) one concept is an instance of a broader one, for example
islands/Sicily or languages/French
(c) sometimes, when one concept is a part of another, for example
eyes/irises or battalions/regiments. But notice that not all whole/part
relationships are eligible for the BT/NT relationship - the most common
allowed cases are for parts of the body, geographical locations,
disciplines, and hierarchical social structures. See fuller explanations
in BS 8723-2 clause 8.3.

If the vocabulary is a taxonomy or a classification scheme, then the
rules of hierarchy tend to be much looser. It is convenient in a library
or a bookshop to be able to browse through, for example, the Chemistry
shelves to find books about chemical elements, chemical laboratories and
even chemists. (Read more about this in the forthcoming BS 8723-3.)

So to use your example, a thesaurus should not allow German politicians
to be treated as a narrower term of Germany (although conceivably these
could be considered as related terms). But a taxonomy or a
classification scheme could allow you to organise these classes
hierarchically if you wished.

While SKOS maintains the ambition of serving a range of vocabulary
types, it will probably have to be hospitable to allowing you to define
as "broader" anything that takes your fancy.

I am tempted to suggest some interesting broader categories for persons
such as Tony Blair and George Bush, but in the name of polite
conversation will resist.

Cheers
Stella


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Stella Dextre Clarke
Information Consultant
Luke House, West Hendred, Wantage, Oxon, OX12 8RR, UK
Tel: 01235-833-298
Fax: 01235-863-298
SDClarke@LukeHouse.demon.co.uk
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-----Original Message-----
From: public-esw-thes-request@w3.org
[mailto:public-esw-thes-request@w3.org] On Behalf Of Richard Cyganiak
Sent: 17 February 2007 17:46
To: public-esw-thes@w3.org
Cc: Sören Auer
Subject: Exactly what does broader/narrower mean?



Hi all,

A quick question.

In Wikipedia, there are often category hierarchies like this:

     Germany
       |
       +-- German politicians

Can this be translated to SKOS? If Germany and German politicians are  
skos:Concepts, then is there a skos:broader relationship between  
them? I'm a bit concerned that one isn't really a sub-topic of the  
other.

To phrase the question differently: Is there a clear test to decide  
if A skos:broader B? For RDFS class hierarchies it's simple: A  
rdfs:subClassOf B iff all instances of A are also instances of B.  
What would be the equivalent rule for SKOS?

Cheers,
Richard
Received on Monday, 19 February 2007 13:00:57 GMT

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