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Re: OWL reasoning in rules

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Tue, 29 May 2007 16:19:08 +0100
Message-ID: <465C446C.2010402@hpl.hp.com>
To: Ulrike Sattler <sattler@cs.man.ac.uk>
CC: Matt Williams <matthew.williams@cancer.org.uk>, Ian Horrocks <horrocks@cs.man.ac.uk>, Owl Dev <public-owl-dev@w3.org>, Semantic Web <semantic-web@w3.org>, Bijan Parsia <bparsia@cs.man.ac.uk>



Wonderful, thanks.

Jeremy

Ulrike Sattler wrote:
> 
> On 29 May 2007, at 15:07, Jeremy Carroll wrote:
> 
>>
>>
>> Ulrike Sattler wrote:
>>> It is not too difficult to see that we can construct an OWL ontology 
>>> all of whose models are infinite (let me know if you want  to see an 
>>> example of such an ontology), e.g., where each model contains an 
>>> infinite chain of fathers *in addition to the fathers that are 
>>> explicitly present in the ontology, 
>>
>>
>> Hmmm, I would like to see a small ontology which is necessarily infinite.
>>
> 
> I meant "an ontology that is consistent (i.e., it has models) but that 
> has no finite models (i.e., only infinite ones)":
> 
> so, here is one (I hope my syntax is ok): zero is an individual, Number 
> and Positive are classes, hasSucc and hasPred are properties --- and I 
> have chosen these names to help you see the structure of a model: 
> 
> %% zero is a number, but not positive
> zero InstanceOf (Number And ComplementOf(Positive)) 
> 
> %% every Number has a positive number as a successor
> Number SubClassOf (some hasSucc (Number And Positive))
>   
> %% hasPred is the inverse of hasSucc
> hasPred (InversePropertyOf hasSucc)
> 
> %%  
> Number SubClassOf (atmost 1 hasPred)
> 
> Cheers, Uli
> 
> 
>> I've just being looking with google, and found my own
>> http://www.w3.org/TR/owl-test/dl-900-arith#description-logic-908
>>
>> which I believe hinges on
>>    2*3*n = 5*n & n>0
>>     implies n >= aleph0,
>> but I am still trying to understand it.
>>
>> thanks for a pointer
>>
>> Jeremy
>>
>>
>>
>> -- 
>> Hewlett-Packard Limited
>> registered Office: Cain Road, Bracknell, Berks RG12 1HN
>> Registered No: 690597 England
>>
> 
> Ulrike Sattler
> sattler@cs.man.ac.uk <mailto:sattler@cs.man.ac.uk>
> http://www.cs.man.ac.uk/~sattler/
> 
> 

-- 
Hewlett-Packard Limited
registered Office: Cain Road, Bracknell, Berks RG12 1HN
Registered No: 690597 England
Received on Tuesday, 29 May 2007 15:19:58 GMT

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