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Re: LANG: feedback on owl proposal

From: Enrico Motta <e.motta@open.ac.uk>
Date: Sun, 24 Mar 2002 16:41:30 +0000
Message-Id: <p05100301b8c3ac183f70@[212.67.106.176]>
To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>, Enrico Motta <e.motta@open.ac.uk>
Cc: www-webont-wg@w3.org
At 9:41 pm +0100 22/3/02, Frank van Harmelen wrote:
>
>>2) 'full cardinality' should be in owl-frame
>
>
>I agree it's a judgement call.
>You could well be right.


well, to quote recent statement from jonathan "_yet_ cardinalities 
really aren't that hard ... everyone who uses XML Schema deals with 
cardinalities etc...". Seems strange that such a basic frame 
construct should not end up in the owl-frame.

>
>
>>3) full set of property specification properties shoud be in 
>>owl-frame (symmetric, transitive, inverseOf, uniquelyDefining, 
>>unambigous, etc..)
>
>
>- Again I agree it's a judgement call, and you could be right.
>- Notice that "inverseOf" was not in our proposal,
>   so that's not just a move but also an addition.

sorry! I meant a move from daml+oil - i.e, daml+oil property 
specification elements should be included.

>- One inverseOf is added, symmetric comes for free.

sure, except that redundancy is a good thing!

>- I would be interested what falls under your "etc.."

Reflexivity is an obvious one.



>
>
>>4) drop 'primitive class & defined class terminology. I have not 
>>been able to come up with better alternatives. , so maybe we could 
>>use a different approach and qualify the attribute specs, rather 
>>than classes.  For instance
>>
>>PrimitiveClass (male, supers(animal))
>>
>>  becomes
>>
>>Class Male (attributeSpec supers(animal))
>>
>>
>>DefinedClass (Man, supers(Person, Male))
>>
>>  becomes
>>
>>Class Man (completelydefiningAttributeSpec supers(Person, Male))
>>
>>A possible extension of this approach could be to allow users to 
>>mix definitional properties with other properties in the same 
>>definition - i.e., attributeSpec and 
>>completelydefiningAttributeSpec could also be used in the same 
>>definition.  For instance:
>>
>>Class Man (completelydefiningAttributeSpec supers(Person, Male),
>>                   (attributeSpec slot (hasAge, range=PositiveInteger)))
>>
>>The above class spec to be interpreted as stating
>>
>>Man (x) <-> (Person (x) and Male (x))
>>(Man (x) and hasAge (x, y)) -> PositiveInteger(y)
>
>
>Interesting suggestion. Need to chew on it.


OK, while you chew let me emphasise that my suggestion has no 
semantic implications. It is simply an attempt to allow DL-style 
specs, without using either the confusing notion of primitive class 
or daml+oil-style statements, where about a class is defined as the 
same as a property restriction.

Enrico
Received on Sunday, 24 March 2002 11:43:08 GMT

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