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OWL2 RL - conformance test question(s)

From: Barry Bishop <barry.bishop@ontotext.com>
Date: Fri, 28 May 2010 18:52:14 +0200
Message-ID: <4BFFF4BE.1030306@ontotext.com>
To: public-owl-dev@w3.org
Hello OWL2 working group,

I would like to ask a couple of fairly straightforward questions
regarding the conformance tests, and the semantics, of the RL profile.

It is very likely that I have missed something fundamental, so I would
be very pleased if someone could nudge me in the right direction.

I have implemented the RDF semantics using the rule set given in:
http://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules

However, I am finding this hard to reconcile with the conformance tests
found here:
http://owl.semanticweb.org/exports/approved/profile-RL.rdf

because some of the expected conclusions of the positive entailment
tests can not by produced by any of the RL entailment rules (I have been
careful to select only those tests labelled with 'test:semantics
test:RDF-BASED').

A couple of specific examples:


Chain2trans
===========
Premise ontology:

<http://example.org/#p> rdf:type owl:ObjectProperty .
_:bnode0 rdf:first <http://example.org/#p> ;
    rdf:rest _:bnode1 .
_:bnode1 rdf:first <http://example.org/#p> ;
    rdf:rest rdf:nil .
<http://example.org/#p> owl:propertyChainAxiom _:bnode0 .

Conclusion ontology:

<http://example.org/#p> rdf:type owl:TransitiveProperty .

Search as I might, I can not find any entailment rules with
owl:TransitiveProperty in the head. So how can this be?


DisjointClasses-001
===================
Premise ontology:

<http://example.org/Boy> rdf:type owl:Class .
<http://example.org/Girl> rdf:type owl:Class .
<http://example.org/Boy> owl:disjointWith <http://example.org/Girl> .
<http://example.org/Stewie> rdf:type <http://example.org/Boy> .

Conclusion ontology:

<http://example.org/Girl> rdf:type owl:Class .
_:bnode1 rdf:type owl:Class ;
    owl:complementOf <http://example.org/Girl> .
<http://example.org/Stewie> rdf:type _:bnode1 .

However, there are no OWL2-RL rules that have blank nodes in the head.

Perhaps I have misunderstood this (in regard to RDFS semantics):

"An OWL 2 RL/RDF implementation MAY include these triples and entailment
rules as necessary without invalidating the conformance requirements for
OWL 2 RL [OWL 2 Conformance]."

- my implementation does not have, for example, RDF(S) se1 & se2 rules.

Or is there some other required behaviour somewhere that I have overlooked?

Many thanks in advance,
barry
Received on Friday, 28 May 2010 21:01:12 GMT

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