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Re: completeness

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Thu, 21 Feb 2008 22:59:42 +0000
Message-Id: <2E22CAB4-E3FF-4DBD-8684-EC6653626353@comlab.ox.ac.uk>
Cc: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, "alan.wu@oracle.com" <alan.wu@oracle.com>, "public-owl-wg@w3.org" <public-owl-wg@w3.org>
To: Jim Hendler <hendler@cs.rpi.edu>

Jim,

I would ask you to recall [1]. It suggested that we try to "confine  
ourselves to technical discussion", to "avoid "interpretation" or  
putting words into other peoples' mouths", and to "look for common  
ground and work towards consensus". I believe that, if you pause to  
reflect, you will agree that this email falls short in several respects.

At this point I would like to call "time out" on this discussion and  
ask that we all take several deep breaths before continuing in "a  
respectful manner".

Regards,
Ian

[1] http://lists.w3.org/Archives/Public/public-owl-wg/2008Jan/0395.html

On 21 Feb 2008, at 21:15, Jim Hendler wrote:

>
> Peter, sorry, not sure what straw person you are attacking- the  
> wiki makes it clear that we outlined a starting place and the key  
> vocabulary elements. The discussion of pd* was, as I understand it,  
> a request to be responsive to questions about formalization and  
> completeness, not an attempt to claim a finished language design.  
> We have not yet set up a mechanism within the WG to do any such  
> discussion and documentation- when the WG has a proposed design we  
> can explore these issues more carefully
>
> Sent from my iPhone
>
> On Feb 21, 2008, at 15:54, "Peter F. Patel-Schneider"  
> <pfps@research.bell-labs.com> wrote:
>
>>
>> From: Alan Wu <alan.wu@oracle.com>
>> Subject: Re: completeness
>> Date: Thu, 21 Feb 2008 14:33:50 -0500
>>
>>> Alan,
>>
>> [...]
>>
>>> In terms of "completeness," I think pD* rules are complete  
>>> (correct me
>>> if I am wrong on this please).
>>
>> Not quite.  The pD* rules need an auxiliary test for contradictions.
>> They could probably be made refutation complete.
>>
>>> And I think pD* vocabulary covers all the
>>> core requirements Oracle sees on the field.
>>
>> I take this to mean that Oracle sees only the following constructs
>> involving vocabulary from the owl: namespace
>>
>> - functional, inversefunctional, symmetric, transitive properties
>> - object equality and inequality
>> - inverse roles
>> - equivalent classes and properties
>> - existential, universal, and filler restrictions
>> - disjoint classes
>>
>> This means no cardinalities at all, nor complements, nor deprecation,
>> nor imports, nor ontology properties, nor use of owl:Thing or
>> owl:Nothing.
>>
>> It also means no inferences *from* existential restrictions, and no
>> inferences *of* universal restrictions.  Also no inferences *of*
>> unmentioned existential restrictions or unmentioned filler  
>> restrictions.
>>
>> Also very limited inference *of* subclass and subproperty  
>> relationships,
>> and equivalent classes and properties.  Similarly, limited inference
>> *of* same individuals and no inference *of* distinct individuals.   
>> Also
>> no inference *of* property functionality, inverse functionality, or
>> symmetricity, transitivity.
>>
>> To see the sort of thing that is lost in pD*, consider that
>>
>> p rdf:type C .
>> q rdf:type D .
>> C owl:disjointWith D .
>>
>> does not pD* entail
>>
>> p owl:differentFrom q .
>>
>> Nor does
>>
>> p r q .
>>
>> pD* entail
>>
>> p rdf:type _:e .
>> _:e owl:hasValue q .
>> _:e owl:onProperty r .
>>
>>
>> Nor does
>>
>> p rdf:type _:s .
>> _:s owl:someValuesFrom C .
>> _:s owl:onProperty r .
>>
>> pD* entail
>>
>> p r _:x .
>>
>> [...]
>>
>>> Zhe
>>
>> peter
>>
>
Received on Thursday, 21 February 2008 22:59:54 GMT

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