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Re: ISSUE-140 (Named Property Chains): Allow (macro-like) shorthands for directly referring to property chains (instead of their superproperty)

From: Rinke Hoekstra <hoekstra@uva.nl>
Date: Thu, 14 Aug 2008 12:33:50 +0200
Message-Id: <AF15492A-7ED6-46F7-A813-5A06AA64CDAF@uva.nl>
To: OWL Working Group WG <public-owl-wg@w3.org>

Updated the issue to exclude number restrictions on named chains.

-Rinke

On 14 aug 2008, at 12:14, OWL Working Group Issue Tracker wrote:

>
>
> ISSUE-140 (Named Property Chains): Allow (macro-like) shorthands for  
> directly referring to property chains (instead of their superproperty)
>
> http://www.w3.org/2007/OWL/tracker/issues/140
>
> Raised by: Rinke Hoekstra
> On product:
>
> (issue raised after discussion with Uli)
>
> Property inclusion axioms are restricted to be the sub property of  
> some other property. For instance:
>
> a o b -> c
>
> An equivalence between the chain and the super property would allow  
> the definition of recursive, and thereby infinite chains, e.g.:
>
> a o b = b
>
> This is hard to reason with: an existential class restriction on b  
> would force such an infinite chain.
>
> However, in many cases it is really useful to be able to point to  
> the chain *directly*. (cf. Nick Drummond's OWLED paper on sequences,  
> Boris' structured objects, and my own work). What this would allow  
> us to do, is force the existence of a sequence of connected  
> individuals by either having an existential (or cardinality) class  
> restriction, or an individual property assertion on the named  
> property chain. We can already enforce a chain of fixed length using  
> nested class restrictions, however these are not as flexible as  
> named property chains (reusability, ABox assertions, substitution in  
> other property chains etc.).
>
> Such named property chain would be a kind of 'macro property chain'  
> so that you can write
>
> 'hasUncle some Rich'
>
> and
>
> 'hasUncle shortfor  hasParent o hasBrother'
>
>
> Uli says:
> This should be harmless since it can simply be handled through  
> preprocessing and macroexpansion.
>
> A restriction is that these 'macro definitions' should be acyclic:  
> then we can reduce ontologies with macros through expansion (i.e.,  
> exhaustively replace macros in value restrictions with their  
> definitions) to ontologies without them.
>
> Impact assessment:
> It would mean touching numerous documents, making sure that, e.g.,  
> each macros is defined not more than once in an ontology, etc...
>
>
>

-----------------------------------------------
Drs. Rinke Hoekstra

Email: hoekstra@uva.nl    Skype:  rinkehoekstra
Phone: +31-20-5253499     Fax:   +31-20-5253495
Web:   http://www.leibnizcenter.org/users/rinke

Leibniz Center for Law,          Faculty of Law
University of Amsterdam,            PO Box 1030
1000 BA  Amsterdam,             The Netherlands
-----------------------------------------------
Received on Thursday, 14 August 2008 10:34:27 GMT

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