Re: SKOS transitive hierarchical relations

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