From: lite.on.beta on

What would aleph0 ^ aleph0 be?
What would aleph1 ^ aleph1 be?

What would cardinality of P^k(N) be?

[That is taking power sets k times on naturals. If k=1, then it is
P(N) = 2^aleph0

c^alpeh_i is easier since c = 2^aleph_0, therefore
c^alpeh_i = 2^aleph_i*aleph0 = 2^aleph_i

Can anyone give me a set with cardinality aleph_1?

No derivations required.
From: William Elliot on
On Mon, 29 Sep 2008 lite.on.beta(a)gmail.com wrote:

> What would aleph0 ^ aleph0 be?
> What would aleph1 ^ aleph1 be?
>
aleph_1 assuming CH
aleph_2 assuming GCH

> What would cardinality of P^k(N) be?
>
> [That is taking power sets k times on naturals. If k=1, then it is
> P(N) = 2^aleph0
>
aleph_k assuming GCH. Without GCH, it's called beth_k.

> c^alpeh_i is easier since c = 2^aleph_0, therefore
> c^alpeh_i = 2^aleph_i*aleph0 = 2^aleph_i
>
> Can anyone give me a set with cardinality aleph_1?
>
The reals, assuming CH of course.

> No derivations required.
>
What? You don't like math?
From: Aatu Koskensilta on
William Elliot <marsh(a)hevanet.remove.com> writes:

> On Mon, 29 Sep 2008 lite.on.beta(a)gmail.com wrote:
>
> > Can anyone give me a set with cardinality aleph_1?
>
> The reals, assuming CH of course.

The set of countable ordinals is the obvious example.

--
Aatu Koskensilta (aatu.koskensilta(a)uta.fi)

"Wovon man nicht sprechen kann, darĂ¼ber muss man schweigen"
- Ludwig Wittgenstein, Tractatus Logico-Philosophicus
From: amy666 on
lite wrote :

>
> What would aleph0 ^ aleph0 be?
> What would aleph1 ^ aleph1 be?

both are aleph_aleph_0.


>
> What would cardinality of P^k(N) be?
>
> [That is taking power sets k times on naturals. If
> k=1, then it is
> P(N) = 2^aleph0
>
> c^alpeh_i is easier since c = 2^aleph_0, therefore
> c^alpeh_i = 2^aleph_i*aleph0 = 2^aleph_i
>
> Can anyone give me a set with cardinality aleph_1?

aleph_aleph_0 is the largest.

you asked for a set with card aleph_1 ; thats just any uncountable set e.g. cantors set.

>
> No derivations required.

regards

tommy1729
From: amy666 on
> lite wrote :
>
> >
> > What would aleph0 ^ aleph0 be?
> > What would aleph1 ^ aleph1 be?
>
> both are aleph_aleph_0.

sorry i read ^^ instead of ^

first is aleph_1 and second is aleph_2.


>
>
> >
> > What would cardinality of P^k(N) be?
> >
> > [That is taking power sets k times on naturals.
> If
> > k=1, then it is
> > P(N) = 2^aleph0
> >
> > c^alpeh_i is easier since c = 2^aleph_0,
> therefore
> > c^alpeh_i = 2^aleph_i*aleph0 = 2^aleph_i
> >
> > Can anyone give me a set with cardinality aleph_1?
>
> aleph_aleph_0 is the largest.
>
> you asked for a set with card aleph_1 ; thats just
> any uncountable set e.g. cantors set.
>
> >
> > No derivations required.
>
> regards
>
> tommy1729

regards

tommy1729