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Re: draft response for LC comment 14

From: Mike Smith <msmith@clarkparsia.com>
Date: Wed, 18 Feb 2009 09:33:22 -0500
Message-ID: <42485a40902180633sc891f8dm80b65205b7ba1b55@mail.gmail.com>
To: W3C OWL Working Group <public-owl-wg@w3.org>
On Mon, Feb 16, 2009 at 16:58, Mike Smith <msmith@clarkparsia.com> wrote:

> [Response for LC Comment 14]

> The definition of ontology entailment in the OWL 2 Direct Semantics
> document [1] is consistent with, and nearly identical to, the
> definition of entailment presented in the OWL Direct Model-Theoretic
> Semantics [2]. The definition of entailment used in the original RDF
> Compatible Semantics [3] and the updated OWL 2 RDF Based Semantics [4]
> differs from the definition used in in Direct Semantics documents.
> Your comment highlights the difference between the Direct and RDF
> based semantics, not a difference between OWL and OWL 2.

Unfortunately, a more careful reading of OWL 1 docs show that the
statements above are incorrect. Entailment in OWL 1 is defined in
terms of interpretations satisfying ontologies.  [2] places the
following constraint on such satisfaction, which is not present in OWL
2.

"each URI reference in O used as a class ID (datatype ID, individual
ID, data-valued property ID, individual-valued property ID, annotation
property ID, annotation ID, ontology ID) belongs to VC (VD, VI, VDP,
VIP, VAP, VO, respectively); "

I will modify the response, along the lines of -- yes it is a change
from OWL 1, but one that permits an empty ontology to entail
tautologies and is a good thing.

-- 
Mike Smith

Clark & Parsia

> [1] http://www.w3.org/2007/OWL/wiki/Direct_Semantics#Inference_Problems
> [2] http://www.w3.org/TR/owl-semantics/direct.html
> [3] http://www.w3.org/TR/owl-semantics/rdfs.html
> [4] http://www.w3.org/2007/OWL/wiki/RDF-Based_Semantics#Satisfaction.2C_Consistency_and_Entailment
> [5] http://www.w3.org/2002/03owlt/Class/Manifest005#test
Received on Wednesday, 18 February 2009 14:34:03 GMT

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