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

From: Ruth Dhanaraj <ruthdhan@gmail.com>
Date: Thu, 9 Jul 2009 20:08:33 -0700
Message-ID: <db7d68190907092008r580369c1v3eeae6a20e3f5d76@mail.gmail.com>
To: Brandon Ibach <bibach@earthlink.net>
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, public-owl-dev@w3.org
There may be more than one property with domain C.... isn't it useful
to have it named for future use? Plus, the resulting info can be
expressed in plain RDF (without OWL)...

Ruth

On Thu, Jul 9, 2009 at 6:57 PM, Brandon Ibach<bibach@earthlink.net> wrote:
> 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 03:09:16 GMT

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