Date: Jan 31, 2013 10:34 AM
Author: mueckenh@rz.fh-augsburg.de
Subject: Re: Matheology § 203
On 31 Jan., 16:15, William Hughes <wpihug...@gmail.com> wrote:

>

> > Would you say that a line that is not in the list is in the list?

>

> Nope. But you did.

Yes, but for an actually infinite list. Cantor's actually infinite

list of all terminating decimals has the property that

every line of the list differs from the antidiagonal

but since the antidiagonal (or at least that initial segment that

contains digits that can be compared with digits of the listed

numbers) is a terminating decimal too, it must be in the list.

Therefore it cannot differ from all entries.

> Both of the above statements are statements

> you have said are true.

>

> My claim is that the first is true and the second is false.

In order prove the second statement false, you have to check complete

0/1 sequences. Compare: In order to prove that card(|N) is larger than

every natural number, you need the complete set. *No* segment (1,

2, ..., 3) of the potentially infinite set |N is larger than every

natural number. Outside of every such segment there are infinitely

many naturals.

Regards, WM