Re: SKOS transitive hierarchical relations

Dear Simon, all,
I'm surely not an expert of SKOS, nor a librarian, but at the latest UDC
seminar I participated I tried to bring the point of view of my research
group (working in knowledge representation and reasoning) in which we
tried to formalize the meaning of the BT\NT relations.

We interpret them as superset/subset and let them correspond to
subsumption in description logic were the interpretation of each node in
the vocabulary is the set of documents about the node. Now, since both
subset and subsumption are transitive, this works only for transitive
BT\NT relations. We treat non transitive BTs as associative relations.

+1,
Enzo


> The problem that with the second version of SKOS (as opposed to the
> original, SME-focused, draft that was stable for about four years) is that
> the traditional  semantics of controlled vocabularies as standardized in
> (e.g. ISO 2788) were rejected, without a corresponding recognition that
> the
> semantics were being changed.
>
> The traditional domain of interpretation for controlled vocabularies is
> #$ConceptualWork; the skos:broader relation in the SME developed
> vocabulary
> corresponded to BT (Broader Term) in controlled vocabularies.
>  Undifferentiated BT is a relationship between subject vocabulary terms,
> and not between #$Collection in an underlying ontological theory.
>
> BT is sometimes referred to in the literature as The Hierarchical
> Relationship; Associative relationships (RT, or skos:related) are the
> residual category of relationships that are neither that of equivalence
> nor
> hierarchical.
> The defining characteristic of hierarchical relationships is that they are
> always true - under NISO standards, intensionally, under ISO 2788
> extensionally for the domain of documents to which the definition applies
> (illustrated in the acceptability and classification of the the turbine -
> blade example).
>
> IT was decided that an essential use case for SKOS required that A broader
> B, B broader C  and not A broader C ; it was also decided that the
> semantics of broader were not changed by this (a deliberate decision was
> made not to change the namespace). I must confess that I am still not
> clear
> on how this is possible, or what broader actually means.
>
> If you want to capture the semantics of Broader Term using the SKOS
> vocabulary, you should assert broaderTransitive and ignore the suggestions
> in the primer. UMBEL has been doing the right thing.
>
> Simon
> Simon
>

Received on Thursday, 5 January 2012 08:58:49 UTC