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Re: owl:allValuesFrom inference

by Sean Bechhofer-2 :: Rate this Message:

On 25 Jun 2009, at 12:30, Sean Bechhofer wrote:

>
> On 25 Jun 2009, at 11:12, Bernhard Schandl wrote:
>
>> Hi,
>>
>>> What you want to say is that *if something is madeby a Man (and
>>> possibly by some other things), then this something is a
>>> ThingMadeByMan.
>>
>> exactly.
>>
>>> So there direction of the implication needs to go the other way
>>> round an you need existential (someValues) restriction... in
>>> Manchester Syntax:
>>>
>>> Class: ThingMadeByMan
>>> EquivalentTo:
>>> madeBy some Man
>>
>> I'm not too familiar with Manchester Syntax, is this equivalent to
>> (n3):
>>
>> ex:ThingMadeByMan
>> a owl:Restriction ;
>> owl:onProperty ex:madeBy ;
>> owl:someValuesFrom ex:Man ;
>> .
>
> No. The N3 above is only asserting *subclass* here.

<cough> Someone (thanks Peter :-) has pointed out to me that I'm
wrong here. The triples above create an owl:Restriction, and then
give it a name, which is not quite how I interpreted it. Note that
this actually pushes you into OWL Full, as you're not allowed to name
a restrictions in OWL DL.

> In M/cr syntax, it's saying:
>
> Class: ThingMadeByMan
> SubClassOf:
> madeBy some Man

The counterpart to the M/cr syntax I gave above would actually be
something like:

ex:ThingMadeByMan
owl:equivalentClass [
a owl:Restriction ;
owl:onProperty ex:madeBy ;
owl:someValuesFrom ex:Man.].

e.g. stating that ThingMadeByMan is equivalent to the appropriate
restriction.

As an aside, this also illustrates how easy it is (well, for me at
least, anyway :-) to get confused by OWL represented as triples. I'd
say it's much easier to see what's going on in an OWL (DL) model if
it's presented using something like M/cr syntax.

Cheers,

Sean

--
Sean Bechhofer
School of Computer Science
University of Manchester
sean.bechhofer@...
http://www.cs.manchester.ac.uk/people/bechhofer

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