while (a=b()) ... infinite sets digression
Carey Evans
c.evans at clear.net.nz
Thu May 20 04:57:07 EDT 1999
graham at sloth.math.uga.edu (Graham Matthews) writes:
> I am not sure I understand this. Surely the set of strings on a finite
> alphabet is countable.
[snip]
I think I get it now.
Imagine an alphabet consisting of the characters `0' to `9'. Now map
this onto decimal numbers like "x1.x2x3x4...xn...", where the length
is infinite. Some of these are 1, 1.3333..., 1.5, 2, 2.718281828...,
3.14159265....
e and pi are transcendental, and are not rational numbers, so (waving
hands) the set of infinite strings over this alphabet is not aleph-0.
(Although I'd like to know how to expand that above 9.999....)
--
Carey Evans http://home.clear.net.nz/pages/c.evans/
"I'm not a god. I've just been misquoted."
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