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Re: SKOS Reference Editor's Draft 23 December 2007

From: Simon Spero <ses@unc.edu>
Date: Wed, 9 Jan 2008 11:32:11 +0000
Message-ID: <1af06bde0801090332l85ca080k9461d21320e4b7dd@mail.gmail.com>
To: "Miles, AJ (Alistair)" <A.J.Miles@rl.ac.uk>
Cc: SKOS <public-esw-thes@w3.org>
[Greetings from Sunny Chigwell]

I'm still really, really uncomfortable with the breakage of  skos:broader,
primarily in regards to the loss of transitivity.

BT relationships in all compliant thesauri must be transitive.

  Each of the relationships should lead to hierarchies that are amenable to
a logical test through reference to the basic types of concept represented
by the terms. (NISO 2005, §8.3)

As an  example of a valid hierarchical relationship and test  (NISO 2005,
Figure 6 ) uses:

*cacti*   ∝ *succulent plants *
SOME *succulent plants* are *cacti*
ALL *cacti* are *succulent plants*
*The example given for an  invalid hierarchical relationship is (NISO 2005,
Figure 7 )

*cacti* ∝ *desert plants *
SOME *desert plants* are *cacti*
SOME *cacti* are *desert plants

A  relationship that does not obey these properties is not hierarchical and
should not be labeled as such.  The relationship is associative, and can be
modeled in SKOS using the appropriate construct (skos:related).    The error
is in the data, not the standard.

Of course, for polyhierarchic structures,   BTG* should not follow  BTP, but
that's a different issue :)

If skos:broader is to be (a) intransitive and (b) useful, there needs to be
a very explicit specification of what the relationship does mean; this will
probably require a complete non-monotonic semantics.

It would be much easier to just add  a new relationship, sortaBroader
subPropertyOf semanticRelation, and leave broader with the standard

Received on Wednesday, 9 January 2008 11:32:17 UTC

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