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RDF semantics: problems with entailment rules rdfs5 and rdfs9

From: <herman.ter.horst@philips.com>
Date: Fri, 7 Nov 2003 11:20:39 +0100
To: pat hayes <phayes@ihmc.us>, www-rdf-comments@w3.org
Message-ID: <OF47881D01.594AB10C-ONC1256DD7.0037A992-C1256DD7.0038E441@diamond.philips.com>

Two rdfs entailment rules do not seem to be stated
in sufficient generality.
This is indicated by the following two counterexamples
to the rdfs entailment lemma.

Example: graph G consists of triples
  x subPropertyOf y
  y subPropertyOf z
where x y and z are blank nodes.
In this case the semantics shows that
G rdfs-entails the triple
  x subPropertyOf z
However this triple is not derived by rule rdfs5,
since this rule requires x y and z to be URIs.

A similar problem occurs with rule rdfs9.

Example: graph H consists of triples
  x subClassOf y
  z type x
where z is a blank node.
According to the semantics, H rdfs-entails the
  z type y
This triple is however not derived by rule rdfs9
since this rule requires z to be a URI.

Herman ter Horst
Received on Friday, 7 November 2003 05:22:53 UTC

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