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Re: SKOS Comment (Reference WD June 2008) - broaderTransitive < broader, narrowerTransitive < narrower

From: Leonard Will <L.Will@willpowerinfo.co.uk>
Date: Sat, 2 Aug 2008 23:47:27 +0100
Message-ID: <+gOPCUK$POlIFAHb@mail.willpowerinfo.co.uk>
To: public-esw-thes@w3.org, public-swd-wg@w3.org

On Sat, 2 Aug 2008 at 14:33:13, Simon Spero <ses@unc.edu> wrote
>On Sat, Aug 2, 2008 at 9:51 AM, Antoine Isaac <aisaac@few.vu.nl> wrote:

>That's why we de-coupled what is not controversial ("this broader was 
>asserted in that thesaurus, and we publisher of the thesaurus want you 
>to know it") from what is useful but should not mess up with initial 
>assertions (broaderTransitive)


>Lets try and clarify things

In the scenario described above,  publisher P asserts:

*A* broader *B*

(Less ambiguously expressed as "A hasBroaderConcept B")

What relationship is being asserted between the extensions of *A* and 
*B* (*
A* and *B*) ?

1)  *A ** B* ?   (All A's are B's )

2)  |*A* * B*|  > |*A* \ *B*| ? (more A's are B's than are not B's)

3)  a.(a  *A*  a  *B*)   b.(b  *B*  b  *A*) ?  ( At least one A 
is
a B and at least one B is not an A)

[Your logic symbols do not travel well in email - better to just use 
words]

To conform to thesaurus standards, if the "broader" relationship is 
generic, then your relationship 1) must apply. The usual example is

Case 1):
parrots BT birds

valid, because all parrots are birds, while only some birds are parrots.

Cases 2) and 3):
parrots BT pets

invalid, because only some parrots are pets and some pets are parrots. 
It seems that these two cases are distinguished only by the degree of 
overlap of the concepts - they would each be represented by RT, if the 
relationship is to be shown at all. The RT relationship is somewhat 
subjective, as "association" is a matter of judgement, following 
guidelines only.

If the relationships in the published thesaurus do not conform to these 
standards, it's anybody's guess what the relationships are, or whether 
they are transitive or not. I don't see how the SKOS version of such a 
thesaurus can include any additional statements specifying that there 
are some valid "broaderTransitive" relationships without examining the 
concepts and determining what valid relationships exist between them - 
i.e. reworking the relationships in the thesaurus. Reconstructing the 
thesaurus in this way would be much more than just encoding it in a SKOS 
format.

Leonard

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Received on Sunday, 3 August 2008 08:28:19 GMT

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