Re: Why isn't FunctionalProperty a subClassOf owl:ObjectProperty?

From: "Bob MacGregor" <macgregor@ISI.EDU>
Subject: Re: Why isn't FunctionalProperty a subClassOf owl:ObjectProperty?


> >Well, neither of these make much sense in OWL DL, domains and ranges of OWL
> >DL datatype properties are disjoint of necessity.

[...]

> Are you claiming that
>
>        :greaterThan :domain :Integer.
>        :greaterThan :range :Integer.
>
> are illegal triples?  If not, then why are my first three triples not
> allowable?

Yes, they are illegal - since Integer is not disjoint with itself.

Again, I think you confuse datatype properties with datatype predicates. Datatype
properties relate individual objects with data values, and datatype predicates
are constraints imposed on the values of datatype properties. OWL support
datatype properties. It makes use of datatypes and datatype predicates defined in
XML Schema.

In your example, greaterThan is a binary datatype predicates. Currently XML
Schema Part 2 supports doesn't support binary datatypes predicates, so OWL
doesn't   support them in its datatype constructs.

If some type systems support binary (or generally speaking, n-ary) datatype
predicates, OWL can be easily extended to support them in its datatype
constructs. E.g. we can define a AllValueFrom restriction like this (assuming
income and expense are functional datatype properties):

AllValueFrom income,expense.greaterThan

it says the value of income should be greater than that of expense. This above
form of restriction is expressible in the SHOQ(Dn) DL [1], which has been proven
to be decidable if the set of datatypes and datatype predicates used is
conforming. In the above example, if we consider the set of datatype and datatype
predicates as {real, not real, greaterThan, lessThanOrEqual}, then it is
conforming.

Hope it helps.

Regards,
Jeff
--
Jeff Z. Pan  ( http://DL-Web.man.ac.uk/ )
Computer Science Dept., The University of Manchester

[1]
http://www.cs.man.ac.uk/~panz/Zhilin/download/Paper/Pan-Horrocks-datatype-2002.pd
f


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> Bob
>
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Received on Thursday, 6 March 2003 05:16:13 UTC