Is subclassing "strict order" or is it reflexive? RE: [sc34wg3] New SAM PSIs

[Anthony B. Coates]

** Reply to message from "Bernard Vatant" <bernard.vatant@mondeca.com> on Mon,
17 Feb 2003 11:10:38 +0100

This doesn't prove that sets and classes are different.  All that you have
proven is that the phrase "Any cat is Murray's friend" was not sufficiently
precise in the first place.

	Meow,
		Tony.

> 	1. "Any cat is Murray's friend"
> 	2. "Any Murray's friend is a cat"
> 
> - A naive set representation of that defines
> 
> C = the set of all cats
> F = the set of all Murray's friends
> 
> You infer that C = F from 1. and 2. 
> 
> That does not make sense, actually, because the "set of all cats" is
> actually impossible to define in extension: All living cats? All the
> cats Murray is likely to meet in his life time? All the cats that have
> ever been and will be? Is the Cheshire's cat in Alice an element of this
> set? etc ...
====
Anthony B. Coates, Information & Software Architect
mailto:abcoates@TheOffice.net
Reuters Messaging: abcoates.londonmarketsystems.com@reuters.net
====
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