RDF MT: rdfs interpretations of subClassOf and subPropertyOf

This came up during a discussion on www-rdf-interest, and while I am
not quite sure I read the logic right, it seems there is an oddness in
the interpretation rules for subClassOf and subPropertyOf in the new
draft of the RDF MT, which I would like clarified.

 From Section 3.3:

  <x,y> is in IEXT(I(rdfs:subClassOf)) if and only if x and y are in IC
  and ICEXT(x) is a subset of ICEXT(y)

Now suppose we have an RDF model which contains a single triple
definining a class:

  <_:MyClass> <rdf:type> <rdfs:Class>

Would not the above condition imply that from this triple we can deduce:

  <_:MyClass> <rdfs:subClassOf> <rdfs:Class>

(since MyClass and rdfs:Class are both in IC and ICEXT(MyClass) is the
  empty set).

Analogously for the interpretation of subPropertyOf.

Am I doing something wrong here, or is this valid, or is it a bug in the
MT?

Best regards,

Jeen
-- 
jeen.broekstra@aidministrator.nl
aidministrator nederland bv - http://www.aidministrator.nl/
julianaplein 14b, 3817 cs amersfoort, the netherlands
tel. +31-(0)33-4659987, fax. +31-(0)33-4659987