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

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netzweltler

Posts: 280
From: Germany
Registered: 8/6/10
Re: Countably Infinite Sets
Posted: Dec 28, 2012 9:16 AM
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On 28 Dez., 03:49, "Ross A. Finlayson" <ross.finlay...@gmail.com>
wrote:
> On Dec 27, 6:43 pm, netzweltler <reinhard_fisc...@arcor.de> wrote:
>

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


"..." means, there is a bijection to the natural numbers

1 -> {1}
2 -> {1,2}
3 -> {1,2,3}
...

>
> Many would include zero.


I cannot see the difference. I could also have asked:
Does the set {{0}, {0,1}, {0,1,2}, ...} contain all natural numbers?




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