SKOS comment: SKOS Primer

Dear SKOS-primer-manager,
I have a question related to the concepts skos:broader vs
skos:broaderTransitive (and similar for narrower).

As I understand the SKOS is explicitly saying that it doesn't say anything
explicit on whether a broader/narrower-relationship is transitive or not.
In order to be explicit transitive, there exists the concepts
skos:broaderTransitive and skos:narrowerTransitive.

This point is further elaborated in  figure 4.5.1 and 4.5.2 in
http://www.w3.org/TR/skos-primer/ - see excerpts below.

But this is where I get confused. Would it not be an error if a reasoner
infer the relationship as transitive anyhow, as it is stated that the
reasoner does? Later it is stated that skos:broader does not inherit
transitiveness from its super-concept. I would expect the example to be
that the author of the KOS would need to explicitly denote the relation as
skos:broaderTransitive in order to achive that fact cats ar animals.


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Consider the example of Fig. 4.5.1 (i):

ex:animals skos:prefLabel "animals"@en.
ex:mammals skos:prefLabel "mammals"@en;
  skos:broader ex:animals.
ex:cats skos:prefLabel "cats"@en;
  skos:broader ex:mammals.

When reading the above triples, a reasoner makes use the definition of
skos:broaderTransitive as a super-property of skos:broader to infer the
following statements:

ex:cats skos:broaderTransitive ex:mammals.
ex:mammals skos:broaderTransitive ex:animals.

The transitivity of skos:broaderTransitive then causes the desired
statement to be inferred:

ex:cats skos:broaderTransitive ex:animals.

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But my intution tells me that there is something that I don't fully
understand ... ;-)


Sincerely,
Steinar Skagemo