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Re: [ontolog-forum] Axioms in Protege

To: cassidy@xxxxxxxxx, "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Adam Pease <adampease@xxxxxxxxxxxxx>
Date: Sat, 16 Aug 2003 09:52:31 -0700
Message-id: <5.0.0.25.0.20030816093937.01a43f50@xxxxxxxxxxxxxxxxxx>
Pat,
   I'll try to explain again in a different way.  If you'll forgive me for 
stating the obvious, languages have specifications, and some languages 
specify syntax, whereas others specify both syntax and 
semantics.  Programming languages for example have both a syntax and a 
semantics.  XML has a syntax, but, as far as I understand, no 
semantics.  Protege and KIF have both syntax and semantics.
   If one has an XML document that includes the following:    (01)

<kif>
(=>
     (and
         (bottom ?BOTTOM ?OBJECT)
         (part ?PART ?OBJECT)
         (not
             (connected ?PART ?BOTTOM)))
     (orientation ?PART ?BOTTOM Above))
</kif>    (02)

you have a valid XML expression that "wraps" a KIF expression.  The 
document is XML, not KIF.  I could have stated:    (03)

<kif>
(=>
     (and
         (bottom ?BOTTOM ?OBJECT)
         (part ?PART ?OBJECT))))))))))))))))))))))
         (not
             (connected ?PART ?BOTTOM)))
     (orientation ?PART ?BOTTOM Above))
</kif>    (04)

This would still be valid XML.  The KIF is syntactically invalid, but no 
XML parser will tell you that.  Similarly, if you put that axiom in a 
Protege ontology, it will accept it happily.  If you had that same KIF 
expression in a KIF file, it would not conform to the syntax and semantics 
specified at <http://suo.ieee.org/suo-kif.html>.  If you try to load the 
second KIF expression into Michal Sevcenko's SUMO browser, it should give 
an error.
   So, it simply is false to say that you've represented the SUMO axioms in 
Protege, just by virtue of including KIF text in a comment field.
   I'm sorry to take so much time for this, but we have to share a basic 
understanding of what it means to write an ontology in a language if we're 
to work as a group on creating an ontology.    (05)

Adam    (06)

A few specified replies:    (07)

At 11:36 PM 8/14/2003 -0400, Patrick Cassidy wrote:
>Adam --
>    I can't figure out where the disagreement is.  We all
>agree that the KIF format will be a canonical representation.
>The only question is whether we will use Protege.  I think
>Protege is useful, and I am trying to find a way to record
>the data in Protege so that it can be exported to a KIF
>file.  Do you think there is something wrong with
>this?
>     It might be useful if you provide a clarification.
>You asked:
>
> > Do you believe that first order logic axioms
> > can be "represented" in XML, because the text can be in a comment?
> >
>    No, I think that first order logic axioms can be represented
>in XML because they can be tagged as axioms, precisely extracted,
>and interpreted as such by the same parser that can interpret the
>axioms in the SUMO file.    (08)

no that's false.  You haven't represented the axioms in XML, you've 
represented them in first order logic, and merely wrapped XML tags around 
those expressions.    (09)

>    I took the SUMO 1.55 data from the text file at:
>
>http://ontology.teknowledge.com/cgi-bin/cvsweb.cgi/SUO/Merge.txt
>
>   In that file, the axioms are represented as bare text, and
>are not marked as axioms (a trivial task I did in importing
>them into Protege).  Do you think that this bare ASCII record is
>a "representation" of the axioms?    (010)

Indeed yes, because those statements conform to a formal specification of 
syntax and semantics as given at <http://suo.ieee.org/suo-kif.html>    (011)

>  The tagged axioms in the
>Protege file recorded as PAL-CONSTRAINTS are byte-for-byte
>copies of the axioms in the SUMO 1.55 file.    (012)

True, but irrelevant.    (013)

>    Is there a different file with the SUMO axioms that you
>feel has a true "representation"?    (014)

No, the SUMO file you have is the representation.    (015)

>  If so, I would appreciate
>getting a copy.
>
>     Regards,
>     Pat
>
>
>
>Adam Pease wrote:
>>Pat,
>>   I'm not sure why there is disagreement on this issue.  I don't 
>> consider the axioms in Protege to be part of its "representation" 
>> because you can't state them in the Protege language - you can only 
>> include them in a comment.  Do you believe that first order logic axioms 
>> can be "represented" in XML, because the text can be in a comment?
>>Adam
>--
>=============================================
>Patrick Cassidy
>
>MICRA, Inc.                      || (908) 561-3416
>735 Belvidere Ave.               || (908) 668-5252 (if no answer)
>Plainfield, NJ 07062-2054        || (908) 668-5904 (fax)
>
>internet:   cassidy@xxxxxxxxx
>=============================================    (016)

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