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Re: int/float disjointness

From: Jos de Bruijn <debruijn@inf.unibz.it>
Date: Wed, 21 Jan 2009 15:34:53 +0100
Message-ID: <4977328D.5070005@inf.unibz.it>
To: Sandro Hawke <sandro@w3.org>
CC: public-rif-wg@w3.org


> Now, in thinking about talking to OWL-WG about this, I'm wondering about
> a few other test cases.  In particular, I think in RIF Core, for the
> empty ruleset:
> 
>    "1"^^xsd:decimal = "1"^^double    IS NOT entailed
> 
> but
> 
>    pred:numeric-equal("1"^^xsd:decimal, "1"^^double)  IS entailed
>    
> Agreed?

Yes.

> 
> The question then, for OWL, is whether it's possible to still have
> 
>    "1"^^xsd:decimal owl:sameAs "1"^^double.   
> 
> be entailed.  Can we still allow that?  

They would need to change the definition of the language, and define
sameAs to be a notion of equality other than identity. They will not
like that. I don't like it either.

If two things are not the same, I don't think a sameAs statement should
be entailed. I suspect the OWL people share this sentiment.

> I think we could implement it in
> OWL-RL, using datatype guards and builtins, as above.

Probably, yes.
It might be a problem for RIF-OWL RL combinations, though.

> 
> I'm trying to figure out whether our "push back" on OWL on this subject
> actually changes their implementations, or is really just about how they
> conceptualize the language.

I don't know how many implementations there are currently that give you
the sameAs entailment. I doubt there are very many.


Best, Jos

> 
>       -- Sandro
> 
> [1] http://www.w3.org/2005/rules/wg/meeting/2009-01-15#resolution_10
> 

-- 
Jos de Bruijn            debruijn@inf.unibz.it
+390471016224         http://www.debruijn.net/
----------------------------------------------
No one who cannot rejoice in the discovery of
his own mistakes deserves to be called a
scholar.
  - Donald Foster


Received on Wednesday, 21 January 2009 14:35:18 GMT

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