[plt-scheme] Natural numbers

From: Norman Gray (norman at astro.gla.ac.uk)
Date: Wed Mar 11 20:33:05 EDT 2009


On 2009 Mar 11, at 23:47, Matthias Felleisen wrote:

> Natural numbers are the counting numbers. You count how many things  
> you have. (The philosophical way to understand "five" is to say that  
> it is what all collection of five objects have in common.)
> The natural (sorry) place to start counting is with 0, having nothing.

In maths, the term "the natural numbers" refers specifically to the  
set of positive integers (see for example [1]), and not to any set  
isomorphic to that.  Thus it does not depend on what you or I may or  
may not find natural, and its meaning is not really a matter for  
dispute.  Anyone who refers, in any sort of semi-formal context, to  
"the natural numbers" as meaning anything other than {n in Z : n > 0}  
is being quixotic.

I don't believe computer scientists have a get-out-of-jail-free card  

Best wishes,


[1] http://eom.springer.de/N/n066090.htm

Norman Gray  :  http://nxg.me.uk
Dept Physics and Astronomy, University of Leicester

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