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Topic: Countably Infinite Sets
Replies: 11   Last Post: Dec 28, 2012 9:08 PM

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Shmuel (Seymour J.) Metz

Posts: 3,473
Registered: 12/4/04
Re: Countably Infinite Sets
Posted: Dec 28, 2012 10:53 AM
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In <virgil-B725AA.22411127122012@BIGNEWS.USENETMONSTER.COM>, on
at 10:41 PM, Virgil <> said:

>In article
> netzweltler <> wrote:

>> Does the set {{1}, {1,2}, {1,2,3}, ...} contain all natural numbers?

>Uunless one's naturals are sets of numerals rather than numerals, or
>sets of sets, as is more usual, it does not contain any of them.

Well, I'm used to seeing the finite ordinals as the model for the
natural numbers; for that it would be {0, {0}, {0,1}, {0,1,2},
{0,1,2,3}, ...}.

Shmuel (Seymour J.) Metz, SysProg and JOAT <>

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