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SKOS Mapping Vocabulary / http://www.w3.org/2004/02/skos/mapping/spec/

From: Martin Hepp <martin.hepp@deri.org>
Date: Tue, 05 Jun 2007 10:39:46 +0200
Message-ID: <46652152.9080407@deri.org>
To: danbri@danbri.org, public-esw-thes@w3.org

Dear Dan, all:

I understand that the SKOS Mapping Vocabulary

http://www.w3.org/2004/02/skos/mapping/spec/

aims at providing a lightweight, consensual formalism for expressing
mapping relations

a) between elements in the same SKOS vocabulary,
b) between elements in multiple SKOS vocabularies, and
c) between elements in a SKOS vocabulary and elements in an RDF-S or OWL
ontology (I am not completely sure whether that is intended but can also
not read that from the Web page).

This is of course a very important contribution. However, I would like
to point out that there is one important difference between
"categorization systems" (or "classifications") on one hand and
ontologies on the other: Classifications *do often NOT have a unique,
context-independent notion of the meaning of a class* - rather, the
intended semantics of a category may vary by context, and people
exchanging classified data must implicitly or explicity agree upon the
context of usage.

For example, we can use the same hierarchical classification of products
and services for classifying

a) actual products and services,
b) staff member who have expertise in particular types of products and
services, or
c) expenses related to a particular type of products and services.

Now, the overall semantics of a category is then no more specific than
"anything that can in any reasonable context be subsumed under the label
XYZ". The problematic thing is, however, that people using
classifications assume a much more restricted intended meaning per category.

Thus, it is problematic to assume that SKOS concepts are also ontology
concepts - a notion that may, if not explicitly intended by SKOS, at
least be assumed by many users of SKOS, and seems to pervade the Mapping
Vocabulary Spec.

We have discussed this issue and how categories in classifications can
be turned into ontology classes in [1]. In our opinion, deriving
concepts with a unique, context-independent semantics from categories in
classifications includes some important modeling choices, which affect
the usefulness of the resulting ontology.

Best

Martin

[1] Martin Hepp, Jos de Bruijn: GenTax: A Generic Methodology for
Deriving OWL and RDF-S Ontologies from Hierarchical Classifications,
Thesauri, and Inconsistent Taxonomies, Proceedings of the 4th European
Semantic Web Conference (ESWC 2007), June 3-7, Innsbruck, Austria, in:
E. Fraconi, M. Kifer, and W. May (Eds.): ESWC 2007, LNCS 4519,  Springer
2007, pp. 129-144.
PDF at http://www.heppnetz.de/files/hepp-de-bruijn-ESWC2007-gentax-CRC.pdf
Received on Tuesday, 5 June 2007 08:40:01 GMT

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