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Re: An inconsistency or not?

From: Minsu Jang <minsu@etri.re.kr>
Date: Thu, 31 Mar 2005 13:40:24 +0900
To: Jeremy Wong <50263336@student.cityu.edu.hk>, Jon Hanna <jon@hackcraft.net>, <semantic-web@w3.org>
Message-ID: <BE71AE48.9CFC%minsu@etri.re.kr>

Thanks to all who replied with helpful discussions.
Now, I can conclude that any two individuals with different names can be
thought of as being equal if there's a set of sentences that entails the
equality of the two, even though there's no explicit assertion that they are
equal.

Now I can see the above conclusion is quite obvious. But then, I think it
suggests many difficult cases for which inference rules cannot easily be
written. Consider the following entailment. (I guess this entailment is
correct.)

A rdf:type owl:Class.
B rdf:type owl:Class.
C rdf:type owl:Class.
D rdf:type owl:Class.
A owl:intersectionOf [B, C, D].
A owl:equivalentClass B.

--->

A owl:equivalentClass C.
A owl:equivalentClass D.
B owl:equivalentClass C.
B owl:equivalentClass D.
C owl:equivalentClass D.

Can any OWL reasoner do this kind of entailment? I'm curious to know, as I'm
experiencing a lot of difficulty due to the cases like above in revising a
set of OWL inference rules for my production rule engine.

Cheers,
Minsu Jang


On 2005.3.31 12:56 PM, "Jeremy Wong" <50263336@student.cityu.edu.hk> wrote:

> 
> 
> Thanks for the explaination. Having the interpretation, both situations
> (owl:sameAs, owl:differentFrom) can be assumed. Consider if John
> owl:differentFrom Johnny is assumed, then the restriction is not satisified.
> Therefore this assumption doesn't satisify. Consider if John owl:sameAs
> Johnny is assumed, then the restriction is satisified. Therefore the facts
> and the axioms are consistent :).
> 
> 
> Jeremy
> 
> ----- Original Message -----
> From: "Jon Hanna" <jon@hackcraft.net>
> To: "'Jeremy Wong'" <50263336@student.cityu.edu.hk>; <semantic-web@w3.org>
> Sent: Thursday, March 31, 2005 11:31 AM
> Subject: RE: An inconsistency or not?
> 
> 
>> Poor my English -_-. Can you explain more on interpreting the
>> sentence
>> involved?
> 
> "...assume either situation is possible"  means to keep an open mind on the
> subject as two which situation is the actual case, in other words to not
> assume that one particular situation is the case (until such a time as this
> is either stated directly, or can be deduced from what is stated).
> 
> Regards,
> Jon Hanna
> Work: <http://www.selkieweb.com/>
> Play: <http://www.hackcraft.net/>
> Chat: <irc://irc.freenode.net/selkie>
> 
> 
> 
> 
Received on Thursday, 31 March 2005 04:40:30 UTC

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