Re: TEST: FunctionalProperty InverseFunctionalProperty 3.4 4.1


is now a
and our tests of that succeeded

same for

-- ,
Jos De Roo, AGFA

Jeremy Carroll <>
Sent by:
2002-08-01 08:32 PM

        To:     Ian Horrocks <>
        cc:     Jeremy Carroll <>,
        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) -> 
> 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

it does not follow that

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 
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.


Received on Friday, 9 August 2002 06:12:07 UTC