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_at_news.tue.nl>
Date: 7 Aug 2001 09:20:54 GMT
Message-ID: <9kobtm$6q$3_at_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 HiddersReceived on Tue Aug 07 2001 - 11:20:54 CEST