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Re: completeness

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 21 Feb 2008 15:54:15 -0500 (EST)
Message-Id: <20080221.155415.255428652.pfps@research.bell-labs.com>
To: alan.wu@oracle.com
Cc: public-owl-wg@w3.org

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 20:59:55 GMT

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