Status of PEP's?

[Bengt Richter]

On Mon, 04 Mar 2002 19:59:03 -0800, David Eppstein <eppstein at ics.uci.edu> wrote:

>In article <7xwuwrofhk.fsf at ruckus.brouhaha.com>,
> Paul Rubin <phr-n2002a at nightsong.com> wrote:
>
>> Usually the term "natural numbers" don't include zero.
>> http://mathworld.wolfram.com/NaturalNumber.html
>
>I think "usually" is an exaggeration.  For instance, a better authority 
>than Weisstein, Ebbinghaus et al's _Numbers_ (Springer Graduate Texts in 
>Mathematics 123, 1991, p. 14) disagrees.

Natural numbers (1, 2, 3 ...) were the only numbers known to the Greeks until
Diophantus thought of fractions, about 275 (though Egyptians apparently had
thought of fractions with one as the numerator before 1700 B.C.). The Greeks
had no symbol for zero. It didn't appear until the fifth century sometime, when Hindus
introduced it. By the twelfth century they had negative integers, but Europeans
didn't catch up to that unitl the sixteenth century and Descartes.

... all this (paraphrased) according to Harriet Griffin's "Elementary Theory of Numbers"
(one of McGraw-Hill's International Series in Pure and Applied Mathematics (c) 1954, p. 1)
(It was a textbook used 1956 at MIT for freshmen, FWIW ;-)

FWIW again, Wordnet agrees also:

[23:32] C:\pywk\telt>wn "natural number" -over

Overview of noun natural_number

The noun natural number has 1 sense (no senses from tagged texts)

1. natural number -- (the number 1 and any other number obtained by adding 1 to it repeatedly)

Regards,
Bengt Richter