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Re: Layering bug?

From: Jos De_Roo <jos.deroo@agfa.com>
Date: Fri, 4 Jul 2003 01:54:32 +0200
To: "pat hayes <phayes" <phayes@ihmc.us>
Cc: www-webont-wg@w3.org
Message-ID: <OFF5F78695.2C406993-ONC1256D58.00811316-C1256D58.008359F1@agfa.be>

>>It is painful, but I will try again to live with
>>owl:Class owl:equivalentClass rdfs:Class.
>>owl:Thing owl:equivalentClass rdfs:Resource.
>>and consider
>>owl:Thing owl:oneOf _:x.
>>as an inconsistent OWL Full document.
>>I guess there are also inconsistent statements
>>about owl:Class ??
>Sure, such as
>owl:Class rdf:type owl:Class .
>which (under the identities assumed in Full) is both RDFS-valid and
>an OWL-inconsistency.  Welcome the wonderful world of layering :-)

Thank you (a bit similar to Brian's sense of thank you as in
"thank you for slapping me about the face with a wet fish").

I had a similar experience which I mentioned in last week's
telecon ie deriving an inconsistency from the empty KB

trying to think in DL and respecting that owl:Class
has a platonic meaning that it can't contain itself
and writing that as

{:owl20k2. owl:Class a owl:Class} =>
  {owl:Class log:inconsistentWith owl:Class}.

we again get from the empty KB

     {[ iw:Variable "?A"] = rdfs:Class.
      [ iw:Variable "?B"] = owl:Class.
      [ iw:Variable "?A"] rdfs:subClassOf [ iw:Variable "?B"]} =>
    {rdfs:Class rdfs:subClassOf owl:Class}.
       {[ iw:Variable "?P"] = rdfs:subClassOf.
        [ iw:Variable "?C"] = rdfs:Class.
        [ iw:Variable "?P"] rdfs:domain [ iw:Variable "?C"]} =>
      {rdfs:subClassOf rdfs:domain rdfs:Class}.
       {[ iw:Variable "?S"] = owl:Class.
        [ iw:Variable "rdfs:subClassOf"] = rdfs:subClassOf.
        [ iw:Variable "?O"] = rdfs:Class.
        [ iw:Variable "?S"] [ iw:Variable "rdfs:subClassOf"] [ iw:Variable
"?O"]} =>
      {owl:Class rdfs:subClassOf rdfs:Class}.
      [ iw:Variable "?S"] = owl:Class.
      [ iw:Variable "?A"] = rdfs:Class.
      [ iw:Variable "?S"] a [ iw:Variable "?A"]} =>
    {owl:Class a rdfs:Class}}  =>
  {owl:Class a owl:Class}.
  [ iw:Variable "?X"] = owl:Class.
  [ iw:Variable "?Y"] = owl:Class.
  [ iw:Variable "?X"] log:inconsistentWith [ iw:Variable "?Y"]} =>
{owl:Class log:inconsistentWith owl:Class}.


Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Thursday, 3 July 2003 19:54:44 GMT

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