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Re: [ontolog-forum] When to use pure subclassing and when to use subclas

To: "'[ontolog-forum] '" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "Rich Cooper" <rich@xxxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 27 Jul 2009 09:11:18 -0700
Message-id: <20090727161129.8F540138CFA@xxxxxxxxxxxxxxxxx>

Hi John,


Those are interesting questions, so I will take a stab at answers that don't fully satisfy me.  Perhaps we can deepen this discussion a bit.






Rich Cooper


Rich AT EnglishLogicKernel DOT com


John Bottoms wrote:


JB> There are a number of programmer's concepts that have not

been explicitly touched upon. Here are my more recent two.


How do we specify between something strong typing and weak

typing in an ontology?


RC> Strong typing is a very valuable construction tool in programming languages because it helps the programmer find inconsistencies in his written expressions.  I don't see the connection between strong typing and ontologies.  It's more a matter of how rigidly and reliably a type can be wiggled by the programmer before the compiler complains.  I can use INTEGER for the number of wheels and not constrain it, but that lets me work with vehicles that have 63 wheels, an unlikely vehicle other than a train, or 0 wheels, like a bicycle in a repair shop. 


So strong typing is useful if I use it to discipline my program writing.  But in an ontology, it’s FINDING out what type an object has that's important - not specifying its type, IMHO. 


And, there is the issue of counts in specifying the number of

items in a set. SGML allows elements to be a)required, b)zero

or more or c)one or more. Actually, I would like to go beyond

that for clarity and have a count or be able to constrain a

count to a range. (Is this the same question as the first one?)


The base type of plurality should be subdivided into different kinds of pluralities - sets, queues, tries ... having a COUNT property built into the class plurality and inherited in one way or another by each structure type. 


For bicycle, I must have 2 wheels.

For vehicle, I might specify it as one or more, to allow for

   motorized unicycles.


For a bicycle, do I have to specify front_wheel and rear_wheel

to assure that I get two wheels?


-John Bottoms


  Concord, MA

  T: 978-505-9878


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