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Re: TEST: FunctionalProperty InverseFunctionalProperty 3.4 4.1

From: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>
Date: Fri, 9 Aug 2002 12:11:20 +0200
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: Ian Horrocks <horrocks@cs.man.ac.uk>, Jeremy Carroll <jjc@hplb.hpl.hp.com>, www-webont-wg@w3.org
Message-ID: <OFA6DD1353.E5A70ED2-ONC1256C10.0036C7DC@agfa.be>

Jeremy,

in http://www.w3.org/2002/03owlt/FunctionalProperty/Manifest
http://www.w3.org/2002/03owlt/FunctionalProperty/Manifest#test003
is now a http://www.w3.org/2002/03owlt/testOntology#NegativeEntailmentTest
and our tests of that succeeded

same for http://www.w3.org/2002/03owlt/InverseFunctionalProperty/Manifest

-- ,
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/




Jeremy Carroll <jjc@hplb.hpl.hp.com>
Sent by: www-webont-wg-request@w3.org
2002-08-01 08:32 PM

 
        To:     Ian Horrocks <horrocks@cs.man.ac.uk>
        cc:     Jeremy Carroll <jjc@hplb.hpl.hp.com>, www-webont-wg@w3.org
        Subject:        Re: TEST: FunctionalProperty InverseFunctionalProperty 3.4 4.1





Ian Horrocks wrote:

> On July 26, Jeremy Carroll writes:
> I am also concerned about tests in the style of FunctionalProperty
> test 003. Here, we are asked to conclude that a property is
> InverseFunctional given that its inverse is functional. This is a
> higher order inference that is a consequence of the semantics of OWL,
> but cannot be proved within OWL. I.e., OWL does not state anything
> like:
>
> forall P,Q . FunctionalProperty(P) ^ inverse(P,Q) -> 
InverseFunctionalProperty(Q)
>
> I would *NOT* expect an OWL reasoner to find this inference.
>



I could support this as a non-entailment test.

As soon as we have an interesting divergence of views it behoves
to make up our minds and choose either an entailment test or
a non-entailment test.


i.e. instead of the comment:

<!--
  If prop is an owl:FunctionalProperty,
  then its inverse is an owl:InverseFunctionalProperty.
-->

We could have the comment

<!--
  If prop is an owl:FunctionalProperty,
  then its inverse, while being constrained to be
  consistent with being an owl:InverseFunctionalProperty
  should not be deduced as being one.
-->


i.e. from

http://www.w3.org/2002/03owlt/FunctionalProperty/premises003.rdf

it does not follow that

http://www.w3.org/2002/03owlt/FunctionalProperty/conclusions003.rdf


This would fit with my preferred reasoning style in which the statements
such as


:inv a owl:InverseFunctionalProperty .

are within the domain of discourse, and have semantic import over and 
above
their definition, which is a necessary but not sufficient condition.

As far as I can see, the non-entailment test follows from a
Connolly/solipsistic/DAML+OIL axiomatic style of semantics

whereas the entailment test reflects a Patel-Schneider view of the
world in which the definition is a neecessary and sufficient condition.


Jeremy
Received on Friday, 9 August 2002 06:12:07 GMT

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