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Re: [ontolog-forum] Foundation ontology, CYC, and Mapping

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From: "sean barker" <sean.barker@xxxxxxxxxxxxx>
Date: Fri, 26 Feb 2010 16:16:11 -0000
Message-id: <529BB0EE68CE41A7ADB34C6A805BDF48@SMB>
Chris and everyone
    Apologies, fried brain sydrome, my implications are back to front, although,
 having corrected them, the orignal arguement should still follow.
Sean Barker, Bristol
Chris Menzel wrote:
On Feb 25, 2010, at 3:57 PM, sean barker wrote:
> ...
> If we define a concept C, which is defined using an axiom Q, and replace Q 
> with an axiom P such that Q implies P but not vice versa (P is "stronger 
> than" Q), then any process that had Q as a post-condition may produce invalid 
> answers.    (01)

Niggling point: You are turning around the usual understandings of "stronger" 
and "weaker".  If Q implies P (Q=>P) but not vice versa, then Q is stronger 
than P and P weaker than Q.  Thought of model theoretically, Q has fewer models 
and hence "says more" than P.    (02)

Less niggling point: Perhaps I am misunderstanding what you have in mind by an 
"answer", but if post-condition Q of a process A is replaced by an axiom P such 
that Q=>P but not vice versa, then every "answer" generated through the use of 
P rather than Q could have been generated by the use of Q.  So if the use of P 
produces invalid answers, so does the use of Q.  Seems to me the danger in 
question arises only if you replace Q with an axiom R such that R=>Q but not 
vice versa.  For then the possibility arises of new answers that could not be 
generated through the use of Q -- answers that are perhaps "invalid" in some 
relevant sense.    (03)

> If we replace Q with a weaker axiom R, such that R implies Q but not vice 
> versa, then any process which uses Q as a precondition can no be used, as 
> the preconditions may be violated.    (04)

Parallel comments here.    (05)

Chris Menzel 

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