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Re: Implementations of LCS for OWL

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 29 Apr 2010 13:58:21 +0100
Message-Id: <D5275267-1C9D-46F7-8538-1061323C9AD7@cs.man.ac.uk>
Cc: Owl Dev <public-owl-dev@w3.org>, sonic@tcs.inf.tu-dresden.de
To: Chris Mungall <cjm@berkeleybop.org>
It's been a while since I thought about LCS in expressive logics  
(i.e., with disjunction...)

On 28 Apr 2010, at 04:18, Chris Mungall wrote:

> I'm looking for efficient implementations of the LCS (least common  
> subsumer) function for OWL. The function take two classes or class  
> expressions C, D and return the minimal class or class expression  
> that subsumes both. Obviously this excludes UnionOf constructs used  
> in the results. Intersection and existential restrictions would be  
> fine.

Well  you have to be a bit careful since just ruling out explicit  
disjunctions is obviously not sufficient, e.g.,
	De Morgan's could bite you, "not C and not D"
	Axioms can bite you, i.e., you return C but C is defined to be D or E.

So you really have to be careful.

> I see there's a vast literature on this going back to the earliest  
> days of DL systems, but surprisingly little in the way of  
> implementations.

It's typically both expensive to compute, is "Sensible" only for very  
restricted logics, and maybe isn't as immediately useful as it might  

> Ideally the implementation would be open source and well-integrated  
> with current tools (e.g. works with the OWLAPI and/or OWLlink). I'd  
> be willing to work a little on the plumbing, but not for closed  
> source tools.

So my first question is about what you need it for and whether true  
LCS is what you need.

Received on Thursday, 29 April 2010 12:58:43 UTC

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