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Re: Semantics of owl:unionOf vs subclass ...

From: Brandon Ibach <bibach@earthlink.net>
Date: Thu, 9 Jul 2009 21:57:57 -0400
Message-ID: <15d6d5d50907091857v2ea7aff4k8dc5dd410e24ae43@mail.gmail.com>
To: Ruth Dhanaraj <ruthdhan@gmail.com>
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, public-owl-dev@w3.org
That depends on what you hope to accomplish with your ontology and why
you're stating a domain for your property.

A property's domain causes an assertion of that property to trigger an
assertion of the property's subject as a member of the class (C, in
your example) given as the property's domain.  Similarly, a subclass
relationship (say, A subclassof C) causes an assertion of an instance
as a member of A to trigger an assertion of that instance as a member
of C.

If the only other facts about the class C are that A and B are
subclasses of it, then membership in that class carries no further
semantics, so what have you gained?

-Brandon :)

On Thu, Jul 9, 2009 at 6:19 PM, Ruth Dhanaraj<ruthdhan@gmail.com> wrote:
> Thanks for the info! Practically speaking, there's little difference
> between the two, correct? If you're not concerned with excluding non
> members of A and B, either syntax should suffice.
> Ruth
> On Thu, Jul 9, 2009 at 2:21 AM, Bijan Parsia<bparsia@cs.man.ac.uk> wrote:
>> On 8 Jul 2009, at 19:31, Ruth Dhanaraj wrote:
>>> Hi,
>>> I've been trying to figure out how I would write a property and say
>>> its domain can be of type A *or* B. The RDF primer says that
>>> specifying multiple domains is an AND, so that's out.
>> Correct.
>>> As far as I can tell, the semantics go something like this:
>>> A subclassof C
>>> B subclassof C
>>> = C is a superset of A u B
>>> C unionOf (A B)
>>> = C is A u B
>>> (then I can say that my property has domain C)
>> You don't need the first two axioms when the latter is an equivalence axiom.
>>> Is this correct? What's the recommended way to specify this?
>> You can do this without introducing a new term (C). I.e., (in no real
>> syntax)
>> p domain unionOf(A B)
>> Some versions of the Protege 3 series would do that by default when you
>> added multiple domains (or ranges).
>> Cheers,
>> Bijan.
Received on Friday, 10 July 2009 15:19:46 UTC

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