Re: completeness

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 21:16:23 UTC