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Re: Owl 1.1 DL and OWL 1.1 Full

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Wed, 7 Nov 2007 10:44:46 -0500
Message-Id: <C266B9E1-04C5-4A58-BF99-B396B3D3FA33@gmail.com>
Cc: OWL Working Group WG <public-owl-wg@w3.org>, Jeremy Carroll <jjc@hpl.hp.com>, Sandro Hawke <sandro@w3.org>
To: Jim Hendler <hendler@cs.rpi.edu>

I have added this issue to the page

Raising it suggests that for completeness we should consider having a  
task to do a more careful audit to expose other such cases.


On Nov 7, 2007, at 9:01 AM, Jim Hendler wrote:

> I was thinking about whether this should be an actual issue or not,  
> but decided to start it here - Depending how I interpret the  
> current documents I can see this being anything from a null issue  
> to a real re-chartering need, so I thought I better bring it up...
> History:
>  if you look at the OWL Requirements and Use Cases [1], you will  
> see that "Effective Decision Procedure" (define as decidability) is  
> an Objective of the language, not a requirement.  We may all have  
> somewhat different memories of how we got to that, but basically,  
> there was not consensus in the group at that point in time that  
> every feature we would want in a Web Ontology Language would be  
> decidable.
>  As it turned out, this came to be important, and the case that  
> really brought it to the fore was the issue of inverseFunctional  
> datatypes.  To make a long story short, the discussions around this  
> issue almost scuttled the Working Group (I was on the phone with  
> the W3C director several times to convince him to let us try to  
> find a way around the impasse), and it was a compromise (brokered  
> by Frank van Harmelen) which led to us having a restricted subset  
> of the language, later called OWL DL, and an unrestricted one,  
> which came to be called OWL Full.
>  This distinction is not artificial - the issues that couldn't be  
> resolved at that time, and some still can't, cause the split  
> between the two branches of OWL, and there are clearly those on the  
> AC, including myself (since i'm not chair and can have an opinion  
> this time), who need and care about OWL Full.
> Issue:
> OK, now to the present - In the OWL 1.1 Web Ontology Language  
> Submission [2], the background makes it very clear that OWL 1.1  
> arose because "an extension of OWL-DL was proposed."  And, in fact,  
> it turns out that the documents for OWL 1.1 do indeed include an  
> extension to OWL DL, but it is unclear, and a real issue, as to how  
> they treat OWL full.  For example, in the BNF for OWL 1.1, the  
> following is included:
> inverseFunctionalObjectProperty :=  
> 'InverseFunctionalObjectProperty' '(' { annotation }  
> objectPropertyExpression ')
> but I can find no similar construct for  
> inverseFunctionalDatatypeProperty - so in essence the OWL Full  
> construct has been ignored completely.
> This could be simple to deal with - these omissions can be easily  
> fixed when a section on OWL 1.1 Full is added to the document
> This could be a charter issue - since it very clearly contradicts  
> the charter [3] statement that
> "All new features should have a clear syntax, and a clear semantics  
> both in terms of OWL DL and OWL Full. The existing compatibility  
> between OWL DL and OWL Full should be preserved, and should be  
> extended to new features wherever possible."
> Impact:
> So, I'm hoping this will be explained as my misunderstanding of the  
> new documents (which I admit I'm still having trouble working out  
> the details of) and not a real issue.  If I'm right, then I am  
> afraid I'll need to oppose publication of the OWL 1.1 documents  
> until something about this is added somewhere, since I think it  
> would be a mistake for the WG to publish working drafts that are in  
> violation of our charter
>  -JH
> p.s. Please note I only discussed inversefunctionaldatatype, but  
> the same goes for all the differentiators of Full vs. DL - and also  
> for new features, cf. my email about Issue 8 which falls under  
> extending OWL Full in the new feature (i.e. allowing a property  
> chain to end in a datatype property should clearly be allowed in  
> OWL 1.1 Full)
> p.p.s. Lest anyone mistake me - I am not claiming this is currently  
> a charter violation, that would be a big step I'm not ready to  
> take, rather I'm asking for clarity on this and on whether it is  
> something the WG needs to take into consideration.
> [1] http://www.w3.org/TR/webont-req/
> [2] http://www.webont.org/owl/1.1/
> [3] http://www.w3.org/2007/06/OWLCharter.html  (may be member  
> readable only, I forget if charters are public)
Received on Wednesday, 7 November 2007 15:45:04 UTC

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