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Re: Clean Object Class Design -- Circle/Ellipse

From: Jan Hidders <hidders_at_REMOVE.THIS.win.tue.nl>
Date: 7 Aug 2001 09:20:54 GMT
Message-ID: <9kobtm$6q$3@news.tue.nl> 






Marc Gluch wrote:


> 

> The only "fool-proof" way of deciding if A is a subtype of B,

> that I know, is to treat A and B as formal theories.




How about this: Algebra A can be a subtype of algebra B if there is an
homomorfism from A to B that preserves the operations.



Could you live with that? :-)


-- 
  Jan Hidders


Received on Tue Aug 07 2001 - 04:20:54 CDT












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