| Any reasonable definition of number that includes "two pi plus
the square root of minus seven" will almost certainly include
"zero". :-)
0 is not prime, its parity is even.
"Number" can be a rather generic term. It is possible to
define specific collections like
positive integers { 1, 2, 3, 4, 5, ... }
non-negative integers { 0, 1, 2, 3, 4, 5, ... }
signed integers { ..., -3, -2, -1, 0, 1, 2, 3, ... }
rational numbers
real numbers
complex numbers
cardinal numbers
ordinal numbers
etc. and then to study such collections along with various
operations on them and embeddings between them etc.
Dan
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|
Don't forget floating point numbers! IEEE specifies which
bit patterns are NaNs, Not a Number. However, all bits zeroes
is considered to be a number. Customers might get upset if
Fortran complained
K=0
----------^
fort: Error: On philisophical grounds, zero is a NaN
This would actually break some applications.
(sorry, couldn;t resist, it's friday)
/Ake
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